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%I #23 Jul 20 2021 14:29:11
%S 1,2,3,4,5,7,43,81,96,98,130,146,162,166,201,205,208,211,221,241,244,
%T 251,271,274,281,300,314,325,333,365,388,422,433,438,443,463,489,519,
%U 559,633,685,793,803,827,857,877,887,1376,1419,1505,1548
%N Numbers whose sum of divisors is palindromic.
%H Amiram Eldar, <a href="/A028980/b028980.txt">Table of n, a(n) for n = 1..10000</a>
%H Patrick De Geest, <a href="http://www.worldofnumbers.com/index.html">World!Of Numbers</a>
%p isA028980 := proc(n)
%p isA002113(numtheory[sigma](n)) ;
%p end proc:
%p for n from 1 to 2000 do
%p if isA028980(n) then
%p printf("%d,",n) ;
%p end if;
%p end do: # _R. J. Mathar_, Sep 09 2015
%t Select[Range[1550],Reverse[x=IntegerDigits[DivisorSigma[1,#]]]==x&] (* _Jayanta Basu_, Jun 05 2013 *)
%t Select[Range[1600],PalindromeQ[DivisorSigma[1,#]]&] (* _Harvey P. Dale_, Jul 20 2021 *)
%Y Cf. A000203, A002113.
%K nonn,base
%O 1,2
%A _Patrick De Geest_
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