G.f.: Sum_{n>=0} x^n / (1-3*x)^(2*n+1) * [Sum_{k=0..n} C(n,k)^2 * 3^k * x^k] * [Sum_{k=0..n} C(n,k)^2 * 4^k * x^k].
A246509
G.f.: Sum_{n>=0} x^n / (1-3*x)^(2*n+1) * [Sum_{k=0..n} C(n,k)^2 * 3^k * x^k] * [Sum_{k=0..n} C(n,k)^2 * 4^k * x^k].
Terms
- a(0) =1a(1) =4a(2) =26a(3) =200a(4) =1694a(5) =15224a(6) =141972a(7) =1359120a(8) =13264246a(9) =131384536a(10) =1316769196a(11) =13323636208a(12) =135885868780
External references
- oeis: A246509