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 A318574 #4 Aug 30 2018 08:37:03
%S A318574 1,1,2,1,3,2,4,1,1,3,5,2,6,4,6,1,7,1,8,3,4,5,9,2,3,6,2,4,10,6,11,1,10,
%T A318574 7,12,1,12,8,3,3,13,4,14,5,3,9,15,2,2,3,14,6,16,2,15,4,8,10,17,6,18,
%U A318574 11,4,1,2,10,19,7,18,12,20,1,21,12,6,8,20,3,22
%N A318574 Denominator of the reciprocal sum of the integer partition with Heinz number n.
%C A318574 The reciprocal sum of (y_1, ..., y_k) is 1/y_1 + ... + 1/y_k. The Heinz number of an integer partition (y_1, ..., y_k) is prime(y_1) * ... * prime(y_k).
%H A318574 Gus Wiseman, <a href="/A051908/a051908.txt">Sequences counting and ranking integer partitions by their reciprocal sums</a>
%F A318574 If n = Product prime(x_i)^y_i is the prime factorization of n, then a(n) is the denominator of Sum y_i/x_i.
%t A318574 Table[Sum[pr[[2]]/PrimePi[pr[[1]]],{pr,If[n==1,{},FactorInteger[n]]}],{n,100}]//Denominator
%Y A318574 Positions of 1's are A316856.
%Y A318574 Cf. A051908, A056239, A058360, A112798, A289506, A289507, A296150, A316854, A316855, A316857, A318573.
%K A318574 nonn,frac
%O A318574 1,3
%A A318574 _Gus Wiseman_, Aug 29 2018