1204736domain: NAppears in sequencesa(n) = Sum_{i=1..floor((n+1)/4)} a(2*i-1) * a(n-2*i+1), with a(1)=2 and a(2)=a(3)=1.at n=19A024735Somos's sequence {b(6,n)} defined in comment in A078495: a(0)=a(1)=...=a(14)=1; for n>=15, a(n)=(a(n-1)*a(n-14)+a(n-7)*a(n-8))/a(n-15).at n=41A271952