A028980 Numbers whose sum of divisors is palindromic.

1, 2, 3, 4, 5, 7, 43, 81, 96, 98, 130, 146, 162, 166, 201, 205, 208, 211, 221, 241, 244, 251, 271, 274, 281, 300, 314, 325, 333, 365, 388, 422, 433, 438, 443, 463, 489, 519, 559, 633, 685, 793, 803, 827, 857, 877, 887, 1376, 1419, 1505, 1548

Offset

1,2

Links

Amiram Eldar, Table of n, a(n) for n = 1..10000

Patrick De Geest, World!Of Numbers

Maple

isA028980 := proc(n)
    isA002113(numtheory[sigma](n)) ;
end proc:
for n from 1 to 2000 do
    if isA028980(n) then
        printf("%d, ", n) ;
    end if;
end do: # R. J. Mathar, Sep 09 2015

Mathematica

Select[Range[1550], Reverse[x=IntegerDigits[DivisorSigma[1, #]]]==x&] (* Jayanta Basu, Jun 05 2013 *)
Select[Range[1600], PalindromeQ[DivisorSigma[1, #]]&] (* Harvey P. Dale, Jul 20 2021 *)

Crossrefs

Cf. A000203, A002113.

Sequence in context: A276522 A135709 A263043 * A183108 A096841 A029963

Adjacent sequences: A028977 A028978 A028979 * A028981 A028982 A028983

Keyword

nonn,base

Author

Patrick De Geest

Status

approved