Problem #27 is one of the many problems on Project Euler that concerns prime numbers. Here is the question: Project Euler Problem 27: Quadratic primes Euler discovered the remarkable quadratic formula: n^2 + n + 41 It turns out that the formula will produce 40 primes for the consecutive integer values 0 ≤ n ≤ …
Tag Archives: Coding
Project Euler Problem #26:
Problem #26 is the first Project Euler problem to feature repeating decimals. The question reads: Project Euler Problem 26: Reciprocal cycles A unit fraction contains 1 in the numerator. The decimal representation of the unit fractions with denominators 2 to 10 are given: 1/2 = 0.5 1/3 = 0.(3) 1/4 = 0.25 1/5 = 0.2 …
Project Euler Problem #25:
Problem #25 is yet another problem where having a background in math makes the problem much easier. It is also another question that concerns the Fibonacci sequence. The question reads: Project Euler Problem 25: 1000-digit Fibonacci number The Fibonacci sequence is defined by the recurrence relation: F_n = F_(n-1)+F_(n-2), where F_1 = 1 and F_2 …
Project Euler Problem #24:
Problem #24 is similar to Problem #15 in that they both commonly appear on introductory math competitions such as the AMC 10/12 and Mathcounts. However, unlike Problem #15, this question is pretty annoying. The question reads: Project Euler Problem 24: Lexicographic permutations A permutation is an ordered arrangement of objects. For example, 3124 is one …
Project Euler Problem #23:
Problem #23 is similar to Problem #21 in that it concerns the sum of the proper divisors of numbers as well as abundant numbers. However, Problem #21 discussed amicable numbers which pair abundant numbers with non-abundant numbers while in this question, we are mostly concerned about abundant numbers. The question reads: Project Euler Problem 23: …
Project Euler Problem #22:
Problem #22 is yet another simple question that involves analyzing a large amount of data. The question reads: Project Euler Problem 22: Names scores Using names.txt (right click and ‘Save Link/Target As…’), a 46K text file containing over five-thousand first names, begin by sorting it into alphabetical order. Then working out the alphabetical value for …
Project Euler Problem #21:
Problem #21 features an obscure type of number known as an amicable number. The problem reads: Project Euler Problem 21: Amicable numbers Let d(n) be defined as the sum of proper divisors of n (numbers less than n which divide evenly into n). If d(a) = b and d(b) = a, where a ≠ b, …
Project Euler Problem #20:
Problem #20 is quite surprisingly the first problem to feature the factorial. I’d explain it, but the question already does it for me. Here’s the question: Project Euler Problem 20: Factorial digit sum n! means n x (n-1) x . . . x 3 x 2 x 1 For example, 10! = 10 x 9 …
Project Euler Problem #19:
Problem #19 is similar to Problem #17 in that it is very painful to implement unless you use an external library in whatever programming language you work in. The question reads: You are given the following information, but you may prefer to do some research for yourself. 1 Jan 1900 was a Monday. Thirty days …
Project Euler Problem #18:
Problem #18 is one of the first problems on Project Euler to prominently feature DP (Dynamic Programming) and the first to explicitly be part of a series of similar problems. The problem reads: Project Euler Problem 18: Maximum path sum I By starting at the top of the triangle below and moving to adjacent numbers …
The Inner Machinations of Walker 