A028568 Palindromes of the form k*(k+8).

0, 9, 33, 4884, 8448, 9009, 31313, 48384, 52425, 82928, 88788, 489984, 505505, 861168, 5013105, 8020208, 48999984, 88322388, 801909108, 902101209, 3305445033, 4899999984, 8807447088, 35565056553, 52065656025, 58129692185, 80532223508, 88892229888, 357468864753

Offset: 1

Author

Patrick De Geest

Keywords

• nonn
• base

Comments

For i >= 0, 48(99)^{2*i}84 is a term arising from k = 69^i6, where ^ is repeated concatenation. - Michael S. Branicky, Jan 30 2022

Links

• Michael S. Branicky, Table of n, a(n) for n = 1..58
• Patrick De Geest, Palindromic Quasipronics of the form n(n+x)

Crossrefs

Intersection of A002113 and A028566.

Cf. A028567.

Programs

Mathematica

Select[Table[k(k+8),{k,0,600000}],PalindromeQ] (* Harvey P. Dale, Jun 24 2023 *)

Formula

a(n) = A028567(n) * (A028567(n) + 8). - Michael S. Branicky, Jan 30 2022

Extensions

a(26) and beyond from Michael S. Branicky, Jan 30 2022