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.

Showing 1-2 of 2 results.

A378936 Number of minimal edge cuts in the n X n rook graph.

Original entry on oeis.org

0, 6, 150, 23214, 14673870, 32893769886, 277707579785790, 9185104346133530814, 1207381826962079773424430, 633579118339962549031587426846, 1329073084589877793324888678089108990, 11149987705045482483752338599907193464092414, 374140639230104433076704980495741968217315823513390
Offset: 1

Views

Author

Andrew Howroyd, Dec 12 2024

Keywords

Crossrefs

Main diagonal of A378935.
Cf. A286189.

Formula

a(n) = A286189(n) + (2^(n-1)-1)^2 - 2^(n^2-1).

A378937 Number of minimal edge cuts in the 2 X n rook graph.

Original entry on oeis.org

1, 6, 22, 84, 346, 1476, 6322, 26844, 112666, 467796, 1925122, 7867404, 31980586, 129475716, 522603922, 2104600764, 8461122106, 33972973236, 136278002722, 546271650924, 2188568145226, 8764722448356, 35090249881522, 140455100761884, 562102748697946, 2249258115629076
Offset: 1

Views

Author

Andrew Howroyd, Dec 12 2024

Keywords

Crossrefs

Row 2 of A378935.
Cf. A134165.

Programs

  • Mathematica
    LinearRecurrence[{10, -35, 50, -24}, {1, 6, 22, 84}, 30] (* Paolo Xausa, Mar 02 2025 *)
  • PARI
    a(n) = 2^(2*n-1) - 3^n + 5*2^(n-1) - 3

Formula

a(n) = A134165(n) - 2.
a(n) = 2^(2*n-1) - 3^n + 5*2^(n-1) - 3.
G.f.: (1 - 4*x - 3*x^2 + 24*x^3)/((1 - x)*(1 - 2*x)*(1 - 3*x)*(1 - 4*x)).
E.g.f.: exp(x)*(2*exp(3*x) - 3*exp(2*x) + 5*exp(x) - 3). - Stefano Spezia, Mar 03 2025
Showing 1-2 of 2 results.