A054263 Number of palindromic triangular numbers with n digits.

3, 2, 3, 3, 2, 2, 6, 2, 1, 4, 7, 0, 4, 4, 12, 5, 6, 2, 3, 2, 6, 3, 6, 2, 2, 4, 3, 2, 5, 0, 3, 2, 1, 4, 3, 1, 10, 1, 4, 0

Offset

1,1

Links

Table of n, a(n) for n=1..40.

P. De Geest, Palindromic Triangulars

Example

a(10) = 4: 1264114621, 1634004361, 5289009825, 6172882716.

Crossrefs

Cf. A000217, A003098, A008509, A008510.

Sequence in context: A275821 A291674 A265157 * A308656 A178775 A124874

Adjacent sequences: A054260 A054261 A054262 * A054264 A054265 A054266

Keyword

nonn,base,hard

Author

Patrick De Geest, Apr 15 2000

Status

approved