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.

A211386 Expansion of 1/((1-2*x)^5*(1-x)).

Original entry on oeis.org

1, 11, 71, 351, 1471, 5503, 18943, 61183, 187903, 553983, 1579007, 4374527, 11829247, 31326207, 81461247, 208470015, 525991935, 1310457855, 3228041215, 7870611455, 19012780031, 45541752831, 108246597631, 255466668031, 598980165631, 1395931480063, 3235049897983
Offset: 0

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Author

R. J. Mathar, Feb 07 2013

Keywords

Comments

Occurs in the enumerations of inflations of code words babxxxdc [Albert et al. Sec 5.5.1]

Crossrefs

Cf. A003472 (first differences).

Programs

  • Mathematica
    CoefficientList[Series[1/((1-2x)^5(1-x)),{x,0,30}],x] (* or *) LinearRecurrence[ {11,-50,120,-160,112,-32},{1,11,71,351,1471,5503},30] (* Harvey P. Dale, Mar 02 2015 *)
  • PARI
    Vec(1/((1-2*x)^5*(1-x))+ O(x^30)) \\ Michel Marcus, Feb 12 2015

Formula

a(n) = 2^n*(24+18*n+23*n^2+6*n^3+n^4)/12-1.
a(0)=1, a(1)=11, a(2)=71, a(3)=351, a(4)=1471, a(5)=5503, a(n)=11*a(n-1)- 50*a(n-2)+ 120*a(n-3)-160*a(n-4)+112*a(n-5)-32*a(n-6). - Harvey P. Dale, Mar 02 2015