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 1-3 of 3 results.

A133803 Floor log A055213(n).

Original entry on oeis.org

4, 8, 12, 15, 18, 21, 24, 26, 29, 31, 33, 35, 38, 39, 41
Offset: 1

Views

Author

Gary W. Adamson, Sep 23 2007

Keywords

Examples

			a(2) = 8 = floor log A055213(2), where A055213(2) = 6972.
		

References

  • Jonathan Schaeffer, N. Burch, Yngvi Bjornsson, Akihiro Kishimoto, Martin Muller, Rob Lake, Paul Lu and Steve Sutphen. "Checkers Is Solved", Science, Vol. 317, September 14, 2007, pp. 1518-1522.

Crossrefs

Cf. A055213.

Formula

Floor log A055213(n), the number of positions in the game of checkers.

A133046 Starting from the standard 12 against 12 starting position in checkers, the sequence gives the number of distinct move sequences after n moves.

Original entry on oeis.org

1, 7, 49, 302, 1469, 7361, 36768, 179740, 845931, 3963680, 18391564, 85242128, 388623673, 1766623630, 7978439499, 36263167175, 165629569428, 758818810990, 3493881706141, 16114043592799, 74545030871553, 345100524480819, 1602372721738102, 7437536860666213, 34651381875296000, 161067479882075800, 752172458688067137, 3499844183628002605, 16377718018836900735, 76309690522352444005
Offset: 0

Views

Author

Jonathan Schaeffer (jonathan(AT)cs.ualberta.ca), Dec 27 2007

Keywords

Comments

Duplicate captures (viz. the situation where a king can capture the same pieces in different directions) are counted separately.

References

  • C. A. Pickover, The Math Book, Sterling, NY, 2009; see p. 512.

Crossrefs

Extensions

a(12)-a(20) computed by Aart Bik and sent by Richard Bean, Sep 18 2009
a(21)-a(26) computed by Aart Bik, with last two completed Sep 18 2012. Rein Halbersma was first to compute a(22). Murray Cash confirmed Aart's a(23) and a(24) results.
a(27)-a(28) first computed by Aart Bik, Sep 2012. Paul Byrne confirmed Aart's a(23)-a(28).
a(29) from Murray Cash, Nov 20 2020

A133047 Starting from the standard 12 against 12 starting position in checkers, the sequence gives the number of distinct positions that can arise after n moves.

Original entry on oeis.org

1, 7, 49, 216, 805, 2733, 9105, 28123, 85340, 255800, 768155, 2265062, 6588759, 18667410, 51448497, 137051636, 353575584, 878804335, 2113497469, 4908984819, 11049271004, 24062242901, 50742319631
Offset: 0

Views

Author

Jonathan Schaeffer (jonathan(AT)cs.ualberta.ca), Dec 27 2007

Keywords

Comments

These numbers are generally smaller than those in A133046 because one line of play can transpose into another.

Crossrefs

Extensions

a(16)-a(22) computed by Paul Byrne, Sep 2012
Showing 1-3 of 3 results.