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.

Previous Showing 21-23 of 23 results.

A182563 Number of ways to place n non-attacking semi-knights on an n x n chessboard.

Original entry on oeis.org

1, 6, 70, 1289, 33864, 1148760, 47700972, 2344465830, 133055587660, 8559364525414, 615266768106190, 48861588247978827, 4247584874013608724, 401107335066453376830, 40880928693752664368224, 4472281486633326131737868
Offset: 1

Views

Author

Vaclav Kotesovec, May 05 2012

Keywords

Comments

Semi-knight is a semi-leaper [1,2]. Moves of a semi-knight are allowed only in [2,1] and [-2,-1]. See also semi-bishops (A187235).

Links

Crossrefs

Cf. A182562, A201540, A201513, A002465, A201511, A197989, A201861.

Formula

Asymptotic: a(n) ~ n^(2n)/n!*exp(-3/2).

Extensions

a(16) from Vaclav Kotesovec, May 24 2021

A245011 Number of ways to place n nonattacking princesses on an n X n board.

Original entry on oeis.org

1, 4, 6, 86, 854, 9556, 146168, 2660326, 56083228, 1349544632, 36786865968, 1117327217782
Offset: 1

Views

Author

Vaclav Kotesovec, Sep 16 2014

Keywords

Comments

A princess moves like a bishop and a knight.

Links

Crossrefs

Cf. A201513, A000170, A002465, A201540.
Cf. A185085, A051223, A244284, A201511, A201861, A137774.
Cf. A225555.

A185056 Number of ways to place n nonattacking composite pieces bishop + semi-rook on an n X n board.

Original entry on oeis.org

1, 2, 5, 24, 125, 796, 5635, 48042, 453947, 4834872, 56433455, 727449366, 10099103269, 152097526360, 2449915208271, 42295879864692
Offset: 1

Views

Author

Vaclav Kotesovec, Dec 22 2011

Keywords

Comments

Two semi-rooks do not attack each other if they are in the same column.

Links

Crossrefs

Cf. A088789, A187235, A002465, A099152, A000170.
Previous Showing 21-23 of 23 results.

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

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