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.

A266229 a(n) = Sum_{j=0..12} (-n)^j.

Original entry on oeis.org

1, 1, 2731, 398581, 13421773, 203450521, 1865813431, 12111126301, 61083979321, 254186582833, 909090909091, 2876892678661, 8230246567621, 21633936185161, 52914318216943, 121637191772461, 264917625139441, 550254335161441
Offset: 0

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Author

Ilya Gutkovskiy, Mar 13 2016

Keywords

Comments

a(n) = Phi_26(n) where Phi_k(x) is the k-th cyclotomic polynomial.

Crossrefs

Cf. similar sequences of the type Phi_k(n) listed in A269442.

Programs

  • GAP
    List([0..20], n-> Sum([0..12], j-> (-n)^j)); # G. C. Greubel, Apr 24 2019
  • Magma
    [(&+[(-n)^j: j in [0..12]]): n in [0..20]]; // G. C. Greubel, Apr 24 2019
    
  • Mathematica
    Table[n^12-n^11+n^10-n^9+n^8-n^7+n^6-n^5+n^4-n^3+n^2-n+1, {n, 0, 17}]
    Table[Cyclotomic[26, n], {n, 0, 17}]
  • PARI
    a(n) = polcyclo(26, n); \\ Michel Marcus, Mar 13 2016
    
  • Sage
    [sum((-n)^j for j in (0..12)) for n in (0..20)] # G. C. Greubel, Apr 24 2019
    

Formula

G.f.: (1 - 12*x + 2796*x^2 + 362870*x^3 + 8453667*x^4 + 59275152*x^5 + 155813880*x^6 + 167535876*x^7 + 74215935*x^8 + 12641708*x^9 + 691692*x^10 + 8022*x^11 + 13*x^12)/(1 - x)^13.
Sum_{n>=0} 1/a(n) = 2.0003687552...

Extensions

Name changed by G. C. Greubel, Apr 24 2019