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A028984 Palindromes whose sum of divisors is odd. 0
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 (list; graph; refs; listen; history; text; internal format)
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

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Last modified July 28 14:19 EDT 2021. Contains 346335 sequences. (Running on oeis4.)