A193191 G.f.: A(x) = Sum_{n>=0} x^n / Product_{k=1..n} (1 - 5^(n-k)*x^k).

1, 1, 2, 7, 53, 887, 32679, 2747187, 508394434, 214213272638, 198419328607654, 418226185357910272, 1937353825293000128681, 20419649837290401081275737, 472970434622490946099542458239, 24925951955494891233466080771797644

Offset

0,3

Links

Table of n, a(n) for n=0..15.

Formula

G.f. satisfies: A(5*x) = Sum_{n>=0} 5^n*x^n/Product_{k=1..n} (1-5^n*x^k).

Example

 G.f.: A(x) = 1 + x + 2*x^2 + 7*x^3 + 53*x^4 + 887*x^5 + 32679*x^6 +...
where:
A(x) = 1 + x/(1-x) + x^2/((1-5*x)*(1-x^2)) + x^3/((1-25*x)*(1-5*x^2)*(1-x^3)) + x^4/((1-125*x)*(1-25*x^2)*(1-5*x^3)*(1-x^4)) +...

Prog

 (PARI) {a(n)=local(A=1); polcoeff(sum(m=0, n, x^m/prod(k=1, m, 1-5^(m-k)*x^k +x*O(x^n))), n)}

Crossrefs

Cf. A193188, A193189, A193190.

Sequence in context: A119772 A104084 A053465 * A180720 A168558 A024027

Adjacent sequences: A193188 A193189 A193190 * A193192 A193193 A193194

Keyword

nonn

Author

Paul D. Hanna, Jul 17 2011

Status

approved