A195903 Numbers m such that m-th centered triangular number is a palindrome.

1, 2, 101, 174, 211, 249, 257, 1822, 2070, 20795, 9531980, 17880587, 215198695, 1702002467, 167526192487, 196759830168, 2036493584526, 17476134422427, 82406037714600, 170438376135142, 181002188703854, 189344689666188, 213031868452710, 10020895012660701, 17108271682888342

Offset

1,2

Comments

Computed by Robert G. Wilson v.

a(18) > 2581988897472. - Donovan Johnson, Sep 29 2011

a(31) > 81649658092772603272. - Patrick De Geest, May 23 2021

Links

Patrick De Geest, Table of n, a(n) for n = 1..30

Terry Trotter, Polygonal numbers [numbers >=920 on this page were incorrect when accessed Sep 25 2011] [Warning: As of March 2018 this site appears to have been hacked. Proceed with great caution. The original content should be retrieved from the Wayback machine and added here. - N. J. A. Sloane, Mar 29 2018]

Terry Trotter, Polygonal Numbers, from the Wayback machine

Patrick De Geest, Palindromic Centered Polygonal Numbers

Crossrefs

Cf. A005448, A162703.

Sequence in context: A171988 A100669 A142050 * A042249 A157338 A064152

Adjacent sequences: A195900 A195901 A195902 * A195904 A195905 A195906

Keyword

nonn,base

Author

Kausthub Gudipati, Sep 25 2011

Extensions

a(14) from D. S. McNeil, Sep 26 2011

a(15)-a(17) from Donovan Johnson, Sep 29 2011

a(18)-a(30) from Patrick De Geest, May 23 2021

Status

approved