162601domain: NPropertiesPrimalityPrimeyesAppears in sequencesExpansion of e.g.f.: exp(Sum_{k>=1} k^2 * x^k).at n=6A255807Square array A(n,k), n >= 0, k >= 0, read by antidiagonals, where column k is the expansion of e.g.f. exp(Sum_{j>=1} j^(k-1)*x^j).at n=51A293785Primes p such that sigma(p+1) = sigma(p+2).at n=3A389277Prime numbersat n=14895