cp's OEIS Frontend

This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.

A182349 G.f.: exp( Sum_{n>=1} 6 * A084214(n) * x^n/n ) where g.f. of A084214 is (1+x^2)/((1+x)*(1-2*x)).

Original entry on oeis.org

1, 6, 30, 120, 435, 1446, 4536, 13560, 39045, 108950, 296178, 787368, 2053335, 5265750, 13306380, 33188040, 81815145, 199585830, 482290630, 1155444120, 2746489851, 6481600326, 15195437280, 35407315800, 82038719565, 189089191926, 433704632346, 990244936520
Offset: 0

Views

Author

Paul D. Hanna, Apr 25 2012

Keywords

Examples

			G.f.: A(x) = 1 + 6*x + 30*x^2 + 120*x^3 + 435*x^4 + 1446*x^5 + 4536*x^6 +...
such that
log(A(x))/6 = x + 4*x^2/2 + 6*x^3/3 + 14*x^4/4 + 26*x^5/5 + 54*x^6/6 + 106*x^7/7 + 214*x^8/8 +...+ A084214(n) * x^n/n +...
		

Crossrefs

Cf. A084214.

Programs

  • Mathematica
    CoefficientList[Series[1/((1+x)^4(1-2x)^5),{x,0,30}],x] (* or *) LinearRecurrence[{6,-6,-24,39,42,-72,-48,48,32},{1,6,30,120,435,1446,4536,13560,39045},30] (* Harvey P. Dale, Aug 11 2021 *)
  • PARI
    {A084214(n)=polcoeff((1+x^2)/((1+x)*(1-2*x+x*O(x^n))), n)}
    {a(n)=polcoeff(exp(sum(k=1, n, 6*A084214(k)*x^k/k)+x*O(x^n)), n)}
    for(n=0, 16, print1(a(n), ", "))

Formula

G.f.: 1/((1+x)^4*(1-2*x)^5).