A171800 a(n) = ((n+1)*2^n + 1)*(2^n + 1)^(n-1).

1, 5, 65, 2673, 397953, 228882753, 520970490625, 4723480504289025, 170687922720157732865, 24563695027660686202250241, 14068441356460459384918212890625, 32058887942708146080692278858371608577, 290694663888102785007861162394348756446314497

Offset

0,2

Links

Vincenzo Librandi, Table of n, a(n) for n = 0..58

Formula

O.G.f.: Sum_{n>=0} (n+1)*2^(n^2) * x^n/(1 - 2^n*x)^(n+1).

E.g.f.: Sum_{n>=0} (n+1)*2^(n^2) * exp(2^n*x) * x^n/n!.

Example

G.f.: A(x) = 1 + 5*x + 65*x^2 + 2673*x^3 + 397953*x^4 +...
A(x) = 1/(1-x) + 2*2*x/(1-2*x)^2 + 3*2^4*x^2/(1-2^2*x)^3 + 4*2^9*x^3/(1-2^3*x)^4 +...

Mathematica

Table[((n + 1)*2^n + 1)*(2^n + 1)^(n - 1), {n, 0, 15}] (* Wesley Ivan Hurt, Jan 19 2017 *)

Prog

(PARI) {a(n)=polcoeff(sum(m=0, n, (m+1)*2^(m^2)*x^m/(1-2^m*x+x*O(x^n))^(m+1)), n)}
(PARI) {a(n)=n!*polcoeff(sum(k=0, n, (k+1)*2^(k^2)*exp(2^k*x)*x^k/k!), n)}
(PARI) {a(n)=((n+1)*2^n+1)*(2^n+1)^(n-1)}

Crossrefs

Cf. A136516, A171801, A171799.

Sequence in context: A012635 A196975 A247540 * A195244 A162080 A012476

Adjacent sequences: A171797 A171798 A171799 * A171801 A171802 A171803

Keyword

nonn,easy

Author

Paul D. Hanna, Jan 20 2010

Status

approved