Problems

1 – 10 of 10

Problem Title Likes Solvers Difficulty

Problem 44862. Ratio between sum of primes and sum of factors

Created by: Jesús Zambrano

Tags primes, factors, ratio

Problem 44229. How brilliant are you?

Created by: James

Tags factors, number theory, brilliant

Problem 1804. Fangs of a vampire number

Created by: Andrew Newell

Tags factors, number theory

Problem 656. Calculate Euler's phi function

Created by: Freddy

Tags math, basic matlab, factors

Problem 577. Repopulate the City

Created by: Ned Gulley

Tags factors

Problem 365. Numbers with prime factors 2, 3 and 5.

Created by: elias GR

Tags primes, factors

287

Problem 1925. Smith numbers

Created by: Sky Sartorius

Tags sum, factors

355

Problem 1825. Find all vampire fangs

Created by: Andrew Newell

Tags factors, number theory

Problem 3075. Matrix of Multiplication Facts

Created by: James

Tags matrix, factors, elementary_school_math

Problem 1826. Find vampire numbers

Created by: Andrew Newell

Tags factors, number theory

250

1 – 10 of 10

Difficulty Rating

Problem Groups

Problems

Problem 44862. Ratio between sum of primes and sum of factors

Problem 44229. How brilliant are you?

Problem 1804. Fangs of a vampire number

Problem 656. Calculate Euler's phi function

Problem 577. Repopulate the City

Problem 365. Numbers with prime factors 2, 3 and 5.

Problem 1925. Smith numbers

Problem 1825. Find all vampire fangs

Problem 3075. Matrix of Multiplication Facts

Problem 1826. Find vampire numbers