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.

A051737 Number of 4 X n (0,1)-matrices with no consecutive 1's in any row or column.

Original entry on oeis.org

1, 8, 41, 227, 1234, 6743, 36787, 200798, 1095851, 5980913, 32641916, 178150221, 972290957, 5306478436, 28961194501, 158061670175, 862654025422, 4708111537971, 25695485730239, 140238391149386, 765379824048327, 4177217595760125, 22798023012345528, 124424893212114297
Offset: 0

Views

Author

Stephen G Penrice, Dec 06 1999

Keywords

Crossrefs

Row 4 of A089934.
Cf. A051736.

Programs

  • Mathematica
    LinearRecurrence[{4, 9, -5, -4, 1}, {1, 8, 41, 227, 1234}, 24] (* Jean-François Alcover, Nov 05 2017 *)
  • PARI
    Vec((1+4*x-4*x^3+x^4)/(1-4*x-9*x^2+5*x^3+4*x^4-x^5) + O(x^50)) \\ Michel Marcus, Sep 17 2014

Formula

From Yong Kong (ykong(AT)curagen.com), Dec 24 2000: (Start)
a(n) = 4*a(n - 1) + 9*a(n - 2) - 5*a(n - 3) - 4*a(n - 4) + a(n - 5);
G.f.: (1 + 4*x - 4*x^3 + x^4)/(1 - 4*x - 9*x^2 + 5*x^3 + 4*x^4 - x^5). (End)
a(n) = 2*a(n - 1) + 18*a(n - 2) + 9*a(n - 3) - 23*a(n - 4) - 2*a(n - 5) + 6*a(n - 6) - a(n - 7).

Extensions

More terms from James Sellers, Dec 08 1999
More terms from Michel Marcus, Sep 17 2014