|
%I #14 May 09 2022 08:37:58
%S 1,6,28,120,364,496,672,840,1080,1488,1782,2280,3276,3472,7440,8128,
%T 8736,11880,12400,18360,20832,24384,25296,26208,30240,30256,32760,
%U 35640,37200,56896,57240,84360,86800,90768,115560,121920,131040,149856,170688
%N Numbers k such that sigma(k) divides k^2.
%H Donovan Johnson, <a href="/A090777/b090777.txt">Table of n, a(n) for n = 1..1000</a>
%t Select[Range[200000], Divisible[#^2, DivisorSigma[1, #]] &] (* _Amiram Eldar_, May 09 2022 *)
%o (PARI) for (n=1,10^6, if ( n^2 % sigma(n) ==0, print1(n,", "))); /* _Joerg Arndt_, May 28 2012 */
%Y Cf. A000203, A000290.
%K nonn
%O 1,2
%A _Benoit Cloitre_, Feb 08 2004
|
