A028984 Palindromes whose sum of divisors is odd.

2, 4, 8, 9, 121, 242, 484, 676, 10201, 12321, 14641, 20402, 24642, 40804, 44944, 69696, 94249, 698896, 1002001, 1234321, 2004002, 2138312, 2468642, 4008004, 5221225, 6948496, 85099058, 100020001, 102030201, 104060401, 121242121

Offset

1,1

Links

Table of n, a(n) for n=1..31.

P. De Geest, Palindromic Squares

Mathematica

Select[Range[2, 122*10^6], PalindromeQ[#]&&OddQ[DivisorSigma[1, #]]&] (* Harvey P. Dale, Aug 01 2020 *)

Crossrefs

Sequence in context: A088274 A118418 A074810 * A294369 A302907 A319561

Adjacent sequences: A028981 A028982 A028983 * A028985 A028986 A028987

Keyword

nonn,base

Author

Patrick De Geest

Status

approved