102259887960domain: NAppears in sequencesNonnegative integers n such that n^2*(n+1)*(2*n+1)^2*(7*n+1)/36 is a square.at n=19A007750Odd bisection of A007750.at n=9A007752Numbers k such that both k+1 and 7k+1 are squares.at n=9A195917