2398417561domain: NAppears in sequencesa(n) = 6*a(n-1) - a(n-2), n >= 2, a(0)=1, a(1)=9.at n=12A038761a(n) = 2*a(n-1) + a(n-2); a(0)=1, a(1)=4.at n=24A0486542*a(n)^2 + 7 is a square.at n=24A077442a(2n) = A001542(n+1), a(2n+1) = A038761(n+1); a Pellian-related sequence.at n=23A129345