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.

A016136 Expansion of 1/((1-2*x)*(1-12*x)).

Original entry on oeis.org

1, 14, 172, 2072, 24880, 298592, 3583168, 42998144, 515977984, 6191736320, 74300836864, 891610044416, 10699320537088, 128391846453248, 1540702157455360, 18488425889497088, 221861110674030592, 2662333328088498176, 31947999937062240256, 383375999244747407360, 4600511990936969936896
Offset: 0

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Examples

			For n=6, a(6) = 2^6+2^7*3+2^8*3^2+2^9*3^3+2^10*3^4+2^11*3^5+2^12*3^6 = 3583168. [_Bruno Berselli_, Aug 28 2013]
		

Programs

  • Magma
    [2^n*(6^(n+1)-1)/5: n in [0..20]]; // Vincenzo Librandi, Oct 09 2011
    
  • Magma
    [&+[2^(n+i)*3^i: i in [0..n]]: n in [0..20]]; // Bruno Berselli, Aug 28 2013
  • Mathematica
    CoefficientList[Series[1/((1 - 2*x)*(1 - 12*x)), {x, 0, 20}], x] (* Wesley Ivan Hurt, Apr 08 2017 *)
  • PARI
    Vec(1/((1-2*x)*(1-12*x))+O(x^99)) \\ Charles R Greathouse IV, Sep 26 2012
    
  • Sage
    [(12^n - 2^n)/10 for n in range(1,18)] # Zerinvary Lajos, Jun 05 2009
    

Formula

a(n) = (12^n - 2^n)/10 for n > 0. - Zerinvary Lajos, Jun 05 2009
From Vincenzo Librandi, Oct 09 2011: (Start)
a(n) = 2^n*(6^(n+1) - 1)/5.
a(n) = 14*a(n-1) - 24*a(n-2). (End)
a(n) = Sum_{i=0..n} 2^(n+i)*3^i. - Bruno Berselli, Aug 28 2013
E.g.f.: exp(2*x)*(exp(10*x) - 1)/10. - Elmo R. Oliveira, Mar 08 2025