187560domain: NAppears in sequencesNonnegative integers n such that 13*n^2 + 13*n + 1 is a square.at n=5A104240Square array A(n,k) (n>=1, k>=1) read by antidiagonals: A(n,k) is the number of n-colorings of the Möbius ladder M_k on 2k vertices.at n=63A277444