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 A161917 #23 Mar 07 2018 11:12:34 %S A161917 12,15,35,42,60,63,66,68,84,90,95,110,114,119,140,143,152,168,189,195, %T A161917 204,209,216,234,245,258,264,270,280,287,290,294,297,319,322,323,352, %U A161917 368,377,380,384,396,470,476,480,506,510,527,531,544,552,558,559,572 %N A161917 Numbers n for which the sum of their prime factors (with repetition) divides the sum of their divisors. %H A161917 Carl R. White, <a href="/A161917/b161917.txt">Table of n, a(n) for n = 1..10000</a> %F A161917 {n: A001414(n) | A000203(n)}. - _R. J. Mathar_, Jun 26 2009 %e A161917 n=12: Sum_divisors (1,2,3,4,6,12) = 28; Sum_prime_factors (2,2,3) =7 -> 28/7 = 4. n=319: Sum_divisors (1,11,29,319) = 360; Sum_prime_factors (11,29) =40 -> 360/40 = 9. %p A161917 with(numtheory); P:=proc(q) local a,n; %p A161917 for n from 2 to q do if not isprime(n) then a:=ifactors(n)[2]; %p A161917 if type(sigma(n)/add(a[k][1]*a[k][2],k=1..nops(a)),integer) then print(n); %p A161917 fi; fi; od; end: P(10^4); %t A161917 Select[Range[2,600],Divisible[DivisorSigma[1,#],Total[ Times@@@ FactorInteger[#]]]&] (* _Harvey P. Dale_, Dec 09 2010 *) %Y A161917 Cf. A161918 %K A161917 easy,nonn %O A161917 1,1 %A A161917 _Paolo P. Lava_ and _Giorgio Balzarotti_, Jun 23 2009 %E A161917 Offset corrected by _R. J. Mathar_, Jun 26 2009