Showing what's behind the curtain

Rooms of Doom

Find the 2000th hexagonal tile in which the differences between it and its 6 neighbors yield 3 primes.

The prime factorisation of binomial coefficients

Powers With Trailing Digits

Find the sum of the distinct square-free numbers in the first 51 rows of Pascal’s triangle.

Find the unique positive integer for a concealed square.

Prime Subset Sums

Find the number of non-empty subsets of {1^{1}, 2^{2}, 3^{3},…, 250250^{250250}}, the sum of whose elements is divisible by 250.

Determining the value of infinite polynomial series for which the coefficients are Fibonacci numbers.

Investigating which primes will never divide a repunit containing 10**n digits.