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.

A332865 Number of placements of zero or more dominoes on the n X n grid where no two empty squares are horizontally adjacent.

Original entry on oeis.org

1, 4, 48, 1427, 140555, 40008789, 33656587715, 84588476099284, 626461671945179295, 13776144517953719025396, 897220763259635483826935324, 173109540246969825014223808529273, 98978509126162805673620043358494745638, 167661422725328648892707605323564506782035252
Offset: 1

Views

Author

Neil A. McKay, Feb 27 2020

Keywords

Comments

The number of positions of n X n Domineering where horizontal (Right) has no moves, also called Right ends. Domineering is a game in which players take turns placing dominoes on a grid, one player placing vertically and the other horizontally until the player to place cannot place a domino.

Links

Crossrefs

Main diagonal of A332862.
Cf. A287595 (the number of placements of dominoes on an n X n grid where no two empty squares are horizontally or vertically adjacent).
Cf. A332714.

Programs

  • Sage
    # See Bjorn Huntemann, Svenja Huntemann, Neil A. McKay link.

Extensions

a(9)-a(14) from Andrew Howroyd, Feb 28 2020

A330658 Number of ways to place zero or more dominoes on an n X n grid with an equal number of horizontal and vertical dominoes.

Original entry on oeis.org

1, 1, 1, 23, 1608, 371500, 328956227, 1126022690953, 14806761014366079, 744494518032208898560, 142687918961909575461700797, 103997384424546478979311463191760, 287748628673335369235353717267441839979, 3018422667417995172483450578913829739500058615
Offset: 0

Views

Author

Andrew Howroyd, Mar 01 2020

Keywords

Examples

			a(1) = a(2) = 1 because the only possibility is placing no dominoes at all.
a(3) = 23 because there is 1 way to place no dominoes, 20 ways to place one horizontal domino and one vertical domino, and 2 ways to place two horizontal and two vertical dominoes.

Crossrefs

Cf. A028420, A332714.
Showing 1-2 of 2 results.

Started in 1964 by Neil J. A. Sloane | Maintained by The OEIS Foundation Inc.

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