A204327 a(n) = Pell(n^2).

1, 12, 985, 470832, 1311738121, 21300003689580, 2015874949414289041, 1111984844349868137938112, 3575077977948634627394046618865, 66992092050551637663438906713182313772, 7316660981177400006023755031791634132229378601

Offset: 1

Author

Paul D. Hanna, Jan 14 2012

Keywords

• nonn

Examples

			G.f.: A(x) = x + 12*x^2 + 985*x^3 + 470832*x^4 + 1311738121*x^5 +...
		

Links

• Seiichi Manyama, Table of n, a(n) for n = 1..51

Crossrefs

Cf. A000129 (Pell), A000290 (n^2), A204274, A165938, A165937, A166879, A054783.

Programs

PARI

{Pell(n)=polcoeff(x/(1-2*x-x^2+x*O(x^n)), n)}
{a(n)=Pell(n^2)}

Formula

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