Find the sum of all pandigital numbers with an unusual sub-string divisibility property.
Find the smallest pair of pentagonal numbers whose sum and difference is pentagonal.
Find the next triangle number that is also pentagonal and hexagonal after 40755
Find the smallest odd composite that cannot be written as the sum of a prime and twice a square.
Find the first four consecutive integers to have four distinct primes factors.
Find the last ten digits of 1^1 + 2^2 + … + 1000^1000.
Find arithmetic sequences, made of prime terms, whose four digits are permutations of each other.
Find the prime number, below one-million, that can be written as the sum of the most consecutive primes.
Find the smallest prime which, by replacing part of the number with the same digit, is part of an eight prime value set.
Find the smallest positive integer, x, such that 2x, 3x, 4x, 5x, and 6x, contain the same digits in some order.