91824010800domain: NAppears in sequencesa(n) = 2*a(n-1) + 2*a(n-3) + a(n-4), with a(0)=1, a(1)=2, a(3)=4, a(4)=10.at n=29A0899282*A084158 (twice Pell triangles).at n=15A114620