Project Euler
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euler1.py sum of Multiples of 3 and 5
euler2.py sum of Even Fibonacci numbers
euler3.py Largest prime factor
euler3.png
16-bit primes all primes <64K
euler4.py Largest palindrome product
euler4.png
euler5.py Smallest multiple.
2520 divisors: 1,2,3,4,5,6,7,8,9,10
euler6.py Sum square difference.
Σi2 vs. (Σi)2
euler7.py 10001st prime
euler8.py Largest product in a series
large matrix
euler9.py Special Pythagorean triplet
i.e. a + b + c = 1000
euler10.py Summation of primes
euler11.py Largest product in a grid *
euler12.py Highly divisible triangular number
factors of triangular nos.
euler13.py Large sum
of many large addends
euler14.py Longest Collatz sequence
Ulam chain
euler15.py Lattice paths
euler16.py Power digit sum
2^1000
euler17.py Number letter counts
speak the number
euler18.py Maximum path sum I
triangle of numbers, top to bottom
euler19.py Counting #Sundays
of the 20th century
euler20.py Factorial digit sum
100!
euler21.py Amicable numbers
sum of proper divisors of a = b and sum of proper divisors of b = a
euler22.py Names scores
5000 names
*euler22_names.txt
euler23.py Non-abundant sums
sum of proper divisors < the number
euler24.py Lexicographic permutations
all permutations in alphabetic order
euler25.py 1000-digit Fibonacci number
euler26.py Reciprocal cycles
repeating patterns of decimal rep of fraction 1/d
euler27.py Quadratic primes. n^2 + an + b
euler27.png
euler28.py Number spiral diagonals
euler29.py Distinct powers.
euler30.py Digit fifth powers.
eg. 1634 = 1^4 + 6^4 + 3^4 + 4^4
euler31.py Coin sums. 2£=
euler32.py Pandigital products.
eg. 39 × 186 = 7254
euler33.py Digit cancelling fractions.
eg. 49/98 = 4/8
euler34.py Digit factorials.
eg. 145=1!+4!+5!
euler35.py Circular primes.
eg. 197, 971, and 719
euler36.py Double-base palindromes.
eg. 585 = 1001001001
euler37.py Truncatable primes.
eg. 3797, 797, 97, and 7, and 379, 37, and 3 all primes.
euler38.py Pandigital concatenated multiples
euler39.py Integer right triangles
eg. perimeter=120: {20,48,52}, {24,45,51}, {30,40,50}
euler40.py Champernowne's constant
0.123456789101112131415161718192021...
euler41.py Pandigital prime
euler42.py Coded triangle numbers
*euler42_words.txt
euler43.py Pandigitals' Sub-string divisibility by primes
euler44.py Pentagon numbers
euler45.py Triangular, pentagonal, and hexagonal numbers
euler46.py Goldbach's other conjecture
every odd composite is sum of a prime and twice a square
euler47.py Distinct primes factors of 4 consecutive integers
euler48.py Self powers 1^1+2^2+3^3+...
euler49.py Prime permutations
euler50.py Consecutive prime sum
euler51.py Prime digit replacements combinations
euler52.py Permuted Multiples
euler53.py Combinatoric Selections
euler54.py Poker Hands *file
euler55.py Lychrel Numbers
euler56.py Powerful Digit Sum
euler57.py Square Root Convergents
euler58.py Spiral Primes
euler59.py XOR Decryption
euler60.py Prime Pair Sets
euler61.py Cyclical Figurate Numbers polygonal nos.
euler62.py Cubic Permutations
euler63.py Powerful Digit Counts n-digit integers also an Nth power
euler65.py Convergents of e sequence of fractional approxs.
euler67.py Maximum Path Sum II weighted binary tree
euler68.py Magic 5-gon Ring int list to str
euler69.py Totient Maximum prime factorization, Euler phi
euler70.py Totient Permutation
euler71.py Ordered Fractions reduced proper fractions, closest to 3/7
euler72.py Counting Fractions totient, Farey sequence
euler73.py Counting Fractions in a Range Farey sequence
euler74.py Digit Factorial Chains sum of digits!
euler75.py Singular Integer Right Triangles gcd()
euler76.py Counting Summations integer partitions
euler77.py Prime Summations
euler78.py * Coin Partitions (generalized) pentagonal numbers
euler79.py Passcode Derivation sets
euler80.py Square Root Digital Expansion *decimal.Decimal precision
euler81.py Path Sum: Two Ways 2D matrix min path to lower right
euler82.py Path Sum: Three Ways 2D matrix min path to left to right
euler85.py * Counting Rectangles sub-rectangles
euler86.py Cuboid Route
euler87.py Prime Power Triples
euler89.py ** Roman Numerals *file
euler.91py Right Triangles with Integer Coordinates
euler92.py Square Digit Chains sequence: sum of squares of digits. 1 or 89
euler96.py ** Su Doku *file
euler97.py Large Non-Mersenne Prime powmod
euler99.py Largest Exponential logs. *File
euler100.py Arranged Probability reduced fraction
euler102.py Triangle Containment (of origin) *file
euler104.py Pandigital Fibonacci Ends
euler107.py Minimal Network min spanning tree, Prim *graph file
euler112.py Bouncy Numbers in/de-creasing digits
euler114.py Counting Block Combinations I
euler115.py Counting Block Combinations II
euler116.py Red, Green, or Blue Tiles math.comb(n,k)
euler117.py Red, Green, and Blue Tiles
euler119.py Digit Power Sum sum_of_digits, sort
euler125.py Palindromic Sums
euler.145py Reversible Numbers re
euler179.py Consecutive Positive *Divisors
euler203.py Squarefree Binomial Coefficients
euler205.py *Dice Game
euler206.py Concealed Square reg ex
euler243.py Resilience totients phi
euler357.py Prime Generating Integers divisors
euler719.py Number Splitting sqrt(n)=sum of split digits of n.
euler757.py Stealthy Numbers N=ab=cd a+b=c+d+1
euler816.py ** Shortest Distance Among Points RNG
euler808.py Reversible Prime Squares s[::-1] string reverse
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