a(n) = Sum_{k=0..n} binomial(n, k)^3 * 2^(n-k) * k!.
A274246
a(n) = Sum_{k=0..n} binomial(n, k)^3 * 2^(n-k) * k!.
Terms
- a(0) =1a(1) =3a(2) =22a(3) =230a(4) =3048a(5) =48152a(6) =875536a(7) =17907024a(8) =405320320a(9) =10030449536a(10) =268836428544
External references
- oeis: A274246