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.

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A008403 G-symmetric Costas arrays of order n that are inequivalent under dihedral group but are not given by the Welch construction.

Original entry on oeis.org

0, 0, 0, 0, 1, 1, 0, 3, 0, 14, 0, 32, 4, 31, 0, 45, 0, 2, 0, 3, 0, 0, 0
Offset: 1

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Author

Keywords

References

  • CRC Handbook of Combinatorial Designs, C. Colbourn and J. Dinitz, Editors, IV.7: Costas Arrays by Herbert Taylor (IV.7.6, page 259, Table 2.29).

Crossrefs

A255981 a(n) = greatest number of edges in a simple polygon on an n X n grid with no two edges parallel.

Original entry on oeis.org

3, 5, 8, 12, 17
Offset: 2

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Author

Gordon Hamilton, Mar 13 2015

Keywords

Comments

Worthy of consideration to introduce slopes in the math classroom.
a(7) >= 23 and a(8) >= 29, see illustration in Links.

Examples

			a(3) = 5 because of this quadrilateral in a 3 x 3 square:
                    1 2 .
                    . 4 .
                    5 . 3
a(4) = 8 because of this polygon:
                   1 3 . 4
                   . . 2 6
                   . . 5 7
                   . 8 . .
		

Crossrefs

Cf. A271449. Construction perhaps related to construction of Costas arrays: A008404.

Extensions

a(5)-a(6) corrected by Hiroaki Yamanouchi, Mar 14 2015

A170808 Number of permutations of 1..n with all differences of elements separated by distances 1 or 2 being respectively unique.

Original entry on oeis.org

1, 2, 4, 12, 40, 116, 252, 768, 2704, 12756, 63168, 338308, 1956876, 11971780, 77909884, 535178056, 3906154920, 30146769464, 244980749052, 2094507398508
Offset: 1

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Author

R. H. Hardin Dec 02 2009

Keywords

Comments

(Empirical) Equals A008404 for n<=2m+2, where m is the maximum difference separation 2.

A170809 Number of permutations of 1..n with all differences of elements separated by distances 1 through 3 being respectively unique.

Original entry on oeis.org

1, 2, 4, 12, 40, 116, 200, 444, 864, 3368, 10936, 38320, 139848, 534828, 2230464, 9802612, 46188544, 231210272, 1213437504, 6717614708, 39002297800
Offset: 1

Views

Author

R. H. Hardin Dec 02 2009

Keywords

Comments

(Empirical) Equals A008404 for n<=2m+2, where m is the maximum difference separation 3.

A170810 Number of permutations of 1..n with all differences of elements separated by distances 1 through 4 being respectively unique.

Original entry on oeis.org

1, 2, 4, 12, 40, 116, 200, 444, 760, 2160, 4872, 11932, 29252, 71708, 191356, 536908, 1607592, 5184252, 17331516, 61597568, 228854684, 891958912
Offset: 1

Views

Author

R. H. Hardin Dec 02 2009

Keywords

Comments

(Empirical) Equals A008404 for n<=2m+2, where m is the maximum difference separation 4.

A170811 Number of permutations of 1..n with all differences of elements separated by distances 1 through 5 being respectively unique.

Original entry on oeis.org

1, 2, 4, 12, 40, 116, 200, 444, 760, 2160, 4368, 7852, 14040, 24284, 42312, 79340, 152764, 320920, 688780, 1577244, 3763512, 9412948
Offset: 1

Views

Author

R. H. Hardin Dec 02 2009

Keywords

Comments

(Empirical) Equals A008404 for n<=2m+2, where m is the maximum difference separation 5.

A170812 Number of permutations of 1..n with all differences of elements separated by distances 1 through 6 being respectively unique.

Original entry on oeis.org

1, 2, 4, 12, 40, 116, 200, 444, 760, 2160, 4368, 7852, 12828, 17252, 21136, 28716, 37276, 53624, 76740, 114856, 180232, 290280
Offset: 1

Views

Author

R. H. Hardin Dec 02 2009

Keywords

Comments

(Empirical) Equals A008404 for n<=2m+2, where m is the maximum difference separation 6.

A170813 Number of permutations of 1..n with all differences of elements separated by distances 1 through 7 being respectively unique.

Original entry on oeis.org

1, 2, 4, 12, 40, 116, 200, 444, 760, 2160, 4368, 7852, 12828, 17252, 19612, 21104, 19760, 20392, 20128, 20636, 22408, 23988
Offset: 1

Views

Author

R. H. Hardin Dec 02 2009

Keywords

Comments

(Empirical) Equals A008404 for n<=2m+2, where m is the maximum difference separation 7.

A170814 Number of permutations of 1..n with all differences of elements separated by distances 1 through 8 being respectively unique.

Original entry on oeis.org

1, 2, 4, 12, 40, 116, 200, 444, 760, 2160, 4368, 7852, 12828, 17252, 19612, 21104, 18276, 15096, 11052, 8484, 6400, 5360
Offset: 1

Views

Author

R. H. Hardin Dec 02 2009

Keywords

Comments

(Empirical) Equals A008404 for n<=2m+2, where m is the maximum difference separation 8.

A170815 Number of permutations of 1..n with all differences of elements separated by distances 1 through 9 being respectively unique.

Original entry on oeis.org

1, 2, 4, 12, 40, 116, 200, 444, 760, 2160, 4368, 7852, 12828, 17252, 19612, 21104, 18276, 15096, 10240, 6464, 3776, 2536
Offset: 1

Views

Author

R. H. Hardin Dec 02 2009

Keywords

Comments

(Empirical) Equals A008404 for n<=2m+2, where m is the maximum difference separation 9.
Previous Showing 11-20 of 21 results. Next