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 1-4 of 4 results.

A383662 Number of closed knight's tours in the first 2n cells of a 6 X ceiling(2n/6) board.

Original entry on oeis.org

6, 0, 2, 302, 8, 151, 19072, 9862, 18202, 1603948, 1067638, 1310791, 107096187, 55488142, 66608924, 6149236417, 3374967940, 4259963914, 402706752421, 239187240144, 292999006211, 26470682075988, 15360134570696, 18595568012716, 1685811256230132, 964730606632516, 1173328484648288
Offset: 11

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Author

Don Knuth, May 04 2025

Keywords

Comments

If n is not a multiple of 3, the rightmost column has only 2n mod 6 rows (see example).

Examples

			For n=11, one of the a(11)=6 solutions is
  1  4 13 16
 12 15  2  5
  3 22 17 14
  8 11  6 19
 21 18  9
 10  7 20   .
		

References

  • Donald E. Knuth, Hamiltonian paths and cycles, Prefascicle 8a of The Art of Computer Programming (work in progress, 2025).

Crossrefs

Formula

a(3n) = A175881(n).

A193054 Number of closed Knight's tours on a 7 X 2n board.

Original entry on oeis.org

0, 0, 1067638, 34524432316, 1250063279938854, 38350427205194670084, 1254934986399237346242334, 40157773188600794694366079616, 1293153423896688571314211086231916, 41575689378315795601749194654016984354, 1337089200028352592236847382536061361269314
Offset: 1

Views

Author

Zhao Hui Du, Jul 15 2011

Keywords

Crossrefs

Formula

a(n) = A383663(7n). - Don Knuth, May 05 2025

A175855 The number of closed Knight's tours on a 5 X 2n board.

Original entry on oeis.org

0, 0, 8, 44202, 13311268, 4557702762, 1495135512514, 491857035772330, 161514101568508400, 53034853662012222798, 17414154188157170439208, 5717847862749642677204182, 1877435447920358266870897874, 616447390029326136628439042672, 202407848349722353779265745190616, 66459727085467788423206394162537418, 21821760546806761707309514948565417796, 7165079447164571822068029945303172129766, 2352622444655438705806553391345493395131580, 772473271844923268504474277422663237674924998
Offset: 1

Views

Author

Johan de Ruiter, Dec 05 2010

Keywords

Examples

			The smallest 5 X 2n board admitting a closed Knight's tour is the 5 X 6, on which there are 8 such tours.
		

Crossrefs

A070030 deals with 3 X 2n boards, A175881 deals with 6 X n boards.
Cf. A383661.

Formula

a(n) = A383661(5n). - Don Knuth, May 05 2025

A193055 Number of closed knight's tours on an 8 X n board.

Original entry on oeis.org

0, 0, 0, 0, 44202, 55488142, 34524432316, 13267364410532, 7112881119092574, 4235482818156697040, 2122880233853945590892, 1105420672289849239070962, 586820057145837880942582376, 311550865881297158579957164664, 162703111270636640083076205067310
Offset: 1

Views

Author

Zhao Hui Du, Jul 15 2011

Keywords

Crossrefs

Programs

  • C
    See Du link.

Formula

a(n) = A383664(4n). - Don Knuth, May 05 2025
Showing 1-4 of 4 results.