cp's OEIS Frontend

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.

A089352 Numbers that are divisible by the sum of their distinct prime factors (A008472).

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%I A089352 #24 Jul 15 2020 04:33:29
%S A089352 2,3,4,5,7,8,9,11,13,16,17,19,23,25,27,29,30,31,32,37,41,43,47,49,53,
%T A089352 59,60,61,64,67,70,71,73,79,81,83,84,89,90,97,101,103,105,107,109,113,
%U A089352 120,121,125,127,128,131,137,139,140,149,150,151,157,163,167,168,169,173
%N A089352 Numbers that are divisible by the sum of their distinct prime factors (A008472).
%C A089352 The Koninck & Luca bound of x / exp(c(1 + o(1))sqrt(log x log log x)) on A158804 applies equally to this sequence. - _Charles R Greathouse IV_, Sep 08 2012
%H A089352 Charles R Greathouse IV, <a href="/A089352/b089352.txt">Table of n, a(n) for n = 1..10000</a>
%H A089352 Jean-Marie de Koninck, Florian Luca, <a href="http://dx.doi.org/10.1112/S0025579300000346">Integers divisible by the sum of their prime factors</a>, Mathematika 52:1-2 (2005), pp. 69-77.
%e A089352 84=2*2*3*7 is divisible by 2+3+7.
%t A089352 primeDivisors[n_] := Select[Divisors[n], PrimeQ]; primeSumDivQ[n_] := 0 == Mod[n, Apply[Plus, primeDivisors[n]]]; Select[Range[2, 300], primeSumDivQ]
%t A089352 Select[Range[2, 175], Divisible[#, Plus @@ First /@ FactorInteger[#]] &] (* _Jayanta Basu_, Aug 13 2013 *)
%o A089352 (PARI) is(n)=my(f=factor(n)[,1]);n%sum(i=1,#f,f[i])==0 \\ _Charles R Greathouse IV_, Feb 01 2013
%Y A089352 Cf. A008472 (sopf).
%Y A089352 Different from A071139.
%K A089352 easy,nonn
%O A089352 1,1
%A A089352 Ramin Naimi (rnaimi(AT)oxy.edu), Dec 26 2003
%E A089352 Name edited by _Michel Marcus_, Jul 15 2020