G.f.: Sum_{n>=0} (n+1)*(n+2)/2 * x^n * ((1+x)^n + 1)^n / (1 + x*(1+x)^n)^(n+3).
A326007
G.f.: Sum_{n>=0} (n+1)*(n+2)/2 * x^n * ((1+x)^n + 1)^n / (1 + x*(1+x)^n)^(n+3).
Terms
- a(0) =1a(1) =3a(2) =9a(3) =22a(4) =81a(5) =285a(6) =1339a(7) =6264a(8) =33567a(9) =186811a(10) =1116105a(11) =7001244a(12) =46150265a(13) =318158826a(14) =2286494076a(15) =17088720336a(16) =132492477111
External references
- oeis: A326007