5790292204domain: NAppears in sequencesa(n) = 2*a(n-1) + a(n-2); a(0)=1, a(1)=4.at n=25A048654Bisection of A048654.at n=12A100525a(2n) = A100525(n), a(2n+1) = A001653(n+1); a Pellian-related sequence.at n=24A129346Integers k such that 2*k^2 - 7 is a square.at n=25A217975