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.

A035038 a(n) = 2^n - C(n,0) - C(n,1) - ... - C(n,5).

Original entry on oeis.org

0, 0, 0, 0, 0, 0, 1, 8, 37, 130, 386, 1024, 2510, 5812, 12911, 27824, 58651, 121670, 249528, 507624, 1026876, 2069256, 4158861, 8344056, 16721761, 33486026, 67025182, 134116144, 268313018, 536724316, 1073567387, 2147277280, 4294724471, 8589650318, 17179537972
Offset: 0

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Comments

Starting with "1", equals the eigensequence of a triangle with A000579 = binomial(n,6) = (1, 7, 28, 84, 210, ...) as the left column and the rest 1's. - Gary W. Adamson, Jul 24 2010

Crossrefs

Programs

  • Haskell
    a035038 n = a035038_list !! n
    a035038_list = map (sum . drop 6) a007318_tabl
    -- Reinhard Zumkeller, Jun 20 2015
    
  • Magma
    [n le 5 select 0 else (&+[Binomial(n,j): j in [6..n]]): n in [0..50]]; // G. C. Greubel, Mar 20 2023
    
  • Maple
    a:= n-> (Matrix(7, (i,j)-> if (i=j-1) then 1 elif j=1 then [8,-27,50,-55, 36,-13,2][i] else 0 fi)^(n))[1,7]:
    seq(a(n), n=0..30);  # Alois P. Heinz, Aug 05 2008
  • Mathematica
    Table[Sum[Binomial[n, k+6], {k,0,n}], {n,0,30}] (* Zerinvary Lajos, Jul 08 2009 *)
    Table[2^n-Total[Binomial[n,Range[0,5]]],{n,0,40}] (* Harvey P. Dale, Oct 24 2017 *)
  • SageMath
    [sum(binomial(n,j) for j in range(6,n+1)) for n in range(51)] # G. C. Greubel, Mar 20 2023

Formula

From Paul Barry, Aug 23 2004: (Start)
G.f.: x^6/((1-2*x)*(1-x)^6).
a(n) = Sum_{k=0..n} C(n, k+6) = Sum_{k=6..n} C(n, k).
a(n) = 2*a(n-1) + C(n-1, 5). (End)