501823476024domain: NAppears in sequencesNonnegative integers n such that n^2*(n+1)*(2*n+1)^2*(7*n+1)/36 is a square.at n=20A007750Even bisection of A007750.at n=10A007751Numbers k such that both k+1 and 7k+1 are squares.at n=10A195917