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.

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A287169 Number of non-attacking king positions on a cylindrical 3 X 2n chessboard.

Original entry on oeis.org

1, 11, 67, 503, 3939, 31111, 246163, 1948503, 15424707, 122107175, 966645747, 7652334327, 60578794275, 479564842183, 3796418256467, 30053895424663, 237918103255427, 1883450483360871, 14910112659965107, 118034140795537975, 934403294669416419, 7397093003809879047
Offset: 0

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Author

Richard M. Low, May 21 2017

Keywords

Crossrefs

Programs

  • Mathematica
    CoefficientList[Series[(1-27*x^2+42*x^3-12*x^4)/(1-11*x+27*x^2-21*x^3+4*x^4), {x, 0, 44}], x] (* Michael De Vlieger, May 21 2017; simplified by Georg Fischer, May 23 2019 *)

Formula

G.f.: (1-27*x^2+42*x^3-12*x^4)/(1-11*x+27*x^2-21*x^3+4*x^4). [Corrected by Georg Fischer, May 23 2019]

A287120 Number of non-attacking bishop positions on a 3 X n chessboard.

Original entry on oeis.org

1, 8, 25, 70, 225, 748, 2401, 7668, 24649, 79344, 255025, 819494, 2634129, 8467464, 27217089, 87483296, 281199361, 903867144, 2905317801, 9338615022, 30017295025, 96485195716, 310134268609, 996870677460, 3204261102025, 10299519778080, 33105949765729, 106413107836334
Offset: 0

Views

Author

Richard M. Low, May 20 2017

Keywords

Crossrefs

Programs

  • Mathematica
    CoefficientList[Series[(-1 - 5 x - x^2 + 7 x^3 + 5 x^4 - x^5 + x^6 - x^7)/(-1 + 3 x + 2 x^3 + 4 x^4 - 10 x^5 - 2 x^6 - x^8 + x^9), {x, 0, 27}], x] (* Michael De Vlieger, May 20 2017 *)
  • PARI
    Vec((-1-5*x-x^2+7*x^3+5*x^4-x^5+x^6-x^7)/ (-1+3*x+2*x^3 +4*x^4-10*x^5-2*x^6-x^8+x^9) + O(x^30)) \\ Michel Marcus, May 20 2017

Formula

G.f.: (-1-5*x-x^2+7*x^3+5*x^4-x^5+x^6-x^7) / (-1+3*x +2*x^3 +4*x^4 -10*x^5 -2*x^6 -x^8 +x^9).
Showing 1-2 of 2 results.