A028571 Palindromes of form k*(k+9).
0, 22, 252, 2332, 20002, 26062, 29392, 63736, 68886, 2701072, 2783872, 2884882, 29122192, 253080352, 289050982, 25661316652, 237776677732, 2393677763932, 215331808133512, 218759969957812, 225588939885522, 235212787212532, 636759171957636, 682911868119286
Offset: 1
Links
- Michael S. Branicky, Table of n, a(n) for n = 1..42
- P. De Geest, Palindromic Quasipronics of the form n(n+x)
Programs
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Mathematica
Select[Table[k(k+9),{k,0,262*10^5}],PalindromeQ] (* Harvey P. Dale, Feb 13 2022 *) -
Python
from itertools import count, islice def ispal(n): s = str(n); return s == s[::-1] def agen(): for k in count(0): if ispal(k*(k+9)): yield k*(k+9) print(list(islice(agen(), 18))) # Michael S. Branicky, Jan 26 2022
Formula
Extensions
a(22) and beyond from Michael S. Branicky, Jan 26 2022