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.

A131529 Number of permutations of {1,2,...n} for which differences of adjacent numbers are all distinct.

Original entry on oeis.org

1, 2, 4, 12, 44, 176, 788, 3936, 23264, 152112, 1104876, 8725320, 74715908, 687915040, 6782261964, 71294227456, 796138700016, 9409401651840, 117378774461812
Offset: 1

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Author

Vladeta Jovovic, Aug 26 2007

Keywords

Crossrefs

Extensions

2 more terms from R. J. Mathar, Oct 25 2007
7 more terms from R. H. Hardin, Nov 26 2009

A206477 (Number of permutations of {1,2,...,n} for which sums of three consecutive numbers (with wraparound) are all distinct)/2n.

Original entry on oeis.org

3, 3, 36, 76, 690, 2996, 22368, 147472, 1284653, 11006509
Offset: 4

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Author

Steve Butler, Feb 08 2012

Keywords

Comments

Essentially different ways 1,2,...,n can be placed around a circle so that sums of three consecutive numbers are distinct.

Examples

			a(4)=3 because up to rotation/reflection the only three permutations which work are 1234, 1243, and 1324
		

Crossrefs

A206478 (Number of permutations of {1,2,...,n} for which sums of four consecutive numbers (with wraparound) are all distinct)/2n.

Original entry on oeis.org

12, 8, 76, 694, 2529, 23679, 177885, 1482021, 14666021
Offset: 5

Views

Author

Steve Butler, Feb 08 2012

Keywords

Comments

Essentially different ways that 1,2,...,n can be placed around a circle so that the sums of three consecutive terms are all distinct.

Examples

			a(6)=8 because up to rotation/reflection the only three permutations which work are 123465, 123546, 124653, 125364, 126543, 132456, 132645, 136524.
		

Crossrefs

A206480 (Number of permutations of {1,2,...,n} for which sums of five consecutive numbers (with wraparound) are all distinct)/2n.

Original entry on oeis.org

60, 46, 690, 2529, 67636, 184014, 2374017, 19353643
Offset: 6

Views

Author

Steve Butler, Feb 08 2012

Keywords

Comments

Essentially different ways 1,2,3,...n can be placed around a circle so that sums of five consecutive numbers are distinct.

Examples

			Some examples of such permutations are: 12568374; 13756824; and 16253847
		

Crossrefs

Showing 1-4 of 4 results.