

A279846


Numbers that are centered kgonal numbers for three or more values of k.


1



1, 31, 37, 43, 46, 61, 67, 73, 79, 85, 91, 106, 109, 121, 127, 133, 136, 145, 151, 157, 166, 169, 181, 199, 211, 217, 226, 232, 235, 241, 253, 265, 271, 274, 277, 289, 295, 301, 307, 313, 316, 325, 331, 337, 343, 361, 379, 391, 397, 406, 409, 421, 433, 451, 463, 469, 481, 496, 505, 511
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OFFSET

1,2


COMMENTS

Numbers satisfying 1 + n*m*(m+1)/2 for three or more values of (n,m), where n >= 0 m > 1.
Numbers in this sequence appear in A101321 at least four times (because the second column contains every positive integer).


LINKS

Daniel Sterman, Table of n, a(n) for a(n)<1000


EXAMPLE

109 is in the sequence because 109 is a centered triangular number, a centered 18gonal number, and a centered 36gonal number.


CROSSREFS

Cf. A062712 (rough equivalent for polygonal numbers).
Cf. A101321 (table of all centered polygonal numbers).
Cf. A275340 (list of nontrivial centered polygonal numbers).
Sequence in context: A051267 A073521 A180540 * A291994 A255223 A230225
Adjacent sequences: A279843 A279844 A279845 * A279847 A279848 A279849


KEYWORD

nonn


AUTHOR

Daniel Sterman, Dec 20 2016


STATUS

approved



