This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.
%I A070222 #19 Feb 24 2024 01:02:52 %S A070222 15,20,24,35,42,54,66,72,95,98,100,104,108,110,114,119,120,126,132, %T A070222 135,140,143,160,168,189,195,207,209,216,220,224,258,264,270,276,287, %U A070222 290,294,319,322,323,351,360,363,375,377,378,384,392,432,440,456,459,464 %N A070222 Numbers k such that the sum of prime divisors of k divides the sum of divisors of k. %H A070222 Amiram Eldar, <a href="/A070222/b070222.txt">Table of n, a(n) for n = 1..10000</a> %e A070222 The sum of divisors of 132 is sigma(132) = 336; prime divisors of 132 are 2,3,11 and (336)/(2+3+11) = 336/16 = 21 hence 132 is in the sequence. %t A070222 Select[Range[2,464], IntegerQ[DivisorSigma[1,#]/Total[First/@FactorInteger[#]]] &] (* _Jayanta Basu_, May 16 2013 *) %o A070222 (PARI) for(n=2,700,if(sigma(n)%sumdiv(n,d,isprime(d)*d)==0,print1(n,","))) %Y A070222 Cf. A000203, A008472. %Y A070222 A037074 is a subsequence. - _Amiram Eldar_, Aug 08 2020 %K A070222 easy,nonn %O A070222 1,1 %A A070222 _Benoit Cloitre_, May 07 2002