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, 3, 2, 2, 1, 3, 3, 0, 0, 9, 0, 3, 2, 4, 3, 5, 0, 4, 2, 2, 0, 4, 7, 3

Offset

1,1

References

Elena Deza and Michel Marie Deza, Figurate numbers, World Scientific Publishing (2012), page 278.

Links

Table of n, a(n) for n=1..63.

Patrick De Geest, Palindromic Triangulars.

Example

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

Crossrefs

Cf. A000217, A002113, A003098, A008509, A008510, A307348

Sequence in context: A275821 A291674 A265157 * A308656 A178775 A124874

Adjacent sequences: A054260 A054261 A054262 * A054264 A054265 A054266

Keyword

nonn,base,hard,more

Author

Patrick De Geest, Apr 15 2000

Extensions

a(41)-a(63) from Patrick De Geest's website added by Max Alekseyev, Jun 03 2026

Status

approved