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 1-6 of 6 results.

A118279 Conjectured number of numbers that are not the sum of three n-gonal numbers, or -1 if infinite.

Original entry on oeis.org

0, -1, 210, 638, 1348, -1, 5282, 7687, 12453, -1, 24813, -1, 45338, -1, 63702, 84764, 109613, -1, 162687, 155879, 224244, -1, 303049, -1, 353690, -1, 522262, 541796, 651844, -1, 817053
Offset: 3

Views

Author

T. D. Noe, Apr 21 2006

Keywords

Comments

See A118278 for the conjectured largest number that is not the sum of three n-gonal numbers.

Crossrefs

Cf. A118278-A118285.

Extensions

a(22)-a(33) from Donovan Johnson, Apr 17 2010

A118282 Conjectured largest number that is not the sum of three generalized n-gonal numbers, or -1 if there is no largest number.

Original entry on oeis.org

0, -1, 0, 0, 307, -1, 2027, 5200, 18180, -1, 10795, -1, 87740, -1, 75150, 212048, 122818, -1, 146970, 199153, 585513
Offset: 3

Views

Author

T. D. Noe, Apr 21 2006

Keywords

Comments

Extensive calculations show that if a(n)>=0, then every number greater than a(n) can be represented as the sum of three generalized n-gonal numbers. a(n)=0 for n=3 and 6 because generalized triangular and generalized hexagonal numbers are the same a triangular numbers and every number can be written as the sum of three triangular numbers. When n is a multiple of 4, there is an infinite set of numbers not representable. For n=14, there appears to be a sparse, but infinite, set of numbers not representable. See A118283 for the number of numbers not representable.

Crossrefs

Cf. A001318 (generalized pentagonal numbers), A085787 (generalized heptagonal numbers), A001082 (generalized octagonal numbers), A118277 (generalized 9-gonal numbers), A118278-A118285.

A118283 Conjectured number of numbers that are not the sum of three generalized n-gonal numbers, or -1 if infinite.

Original entry on oeis.org

0, -1, 0, 0, 4, -1, 26, 45, 94, -1, 196, -1, 370, -1, 641, 743, 999, -1, 1537, 1429, 2619
Offset: 3

Views

Author

T. D. Noe, Apr 21 2006

Keywords

Comments

See A118282 for the conjectured largest number that is not the sum of three generalized n-gonal numbers. For n=7, only four numbers are not representable: 10, 16, 76 and 307.

Crossrefs

Cf. A118278-A118285.

A118280 Conjectured largest number that is not the sum of three (2n+1)-gonal numbers; bisection of A118278.

Original entry on oeis.org

0, 33066, 273118, 1274522, 3613278, 7250758, 12911636, 22655394, 25049533, 56922533, 81539010, 85105105, 106555658, 233296317, 286763923, 358322750
Offset: 1

Views

Author

T. D. Noe, Apr 21 2006

Keywords

Crossrefs

Cf. A118278-A118285.

Extensions

a(11)-a(16) from Donovan Johnson, Apr 17 2010

A118281 Conjectured number of numbers that are not the sum of three (2n+1)-gonal numbers; bisection of A118279.

Original entry on oeis.org

0, 210, 1348, 5282, 12453, 24813, 45338, 63702, 109613, 162687, 224244, 303049, 353690, 522262, 651844, 817053
Offset: 1

Views

Author

T. D. Noe, Apr 21 2006

Keywords

Crossrefs

Cf. A118278-A118285.

Extensions

a(11)-a(16) from Donovan Johnson, Apr 17 2010

A118284 Conjectured largest number that is not the sum of three generalized (2n+1)-gonal numbers; bisection of A118282.

Original entry on oeis.org

0, 0, 307, 2027, 18180, 10795, 87740, 75150, 122818, 146970, 585513
Offset: 1

Views

Author

T. D. Noe, Apr 21 2006; revised Apr 23 2006

Keywords

Crossrefs

Cf. A118278-A118285.
Showing 1-6 of 6 results.

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

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