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 A384498 #24 Jun 02 2025 09:50:23
%S A384498 1,30,70,286,646,1798,2145,2310,2730,3135,3526,3570,4641,4845,5005,
%T A384498 5610,6006,6279,6630,7198,7410,7854,8778,8855,8970,9177,10366,10374,
%U A384498 10626,10695,11305,11571,11730,13110,13485,13566,13585,15470,16095,16302,16422,16530
%N A384498 Squarefree numbers whose distinct prime factors can be partitioned into two sets with equal sums.
%H A384498 Alois P. Heinz, <a href="/A384498/b384498.txt">Table of n, a(n) for n = 1..10000</a>
%e A384498 2145 = 3*5*11*13 is a term because it is squarefree and 3+13 = 5+11.
%e A384498 16422 = 2*3*7*17*23 is squarefree and 2+7+17 = 3+23.
%p A384498 q:= n-> (l-> {l[.., 2][]} minus {1}={} and (s->
%p A384498 (m-> m::even and coeff(mul(1+x^j, j=s), x, m/2)>0)
%p A384498 (add(i, i=s)))({l[.., 1][]}))(ifactors(n)[2]):
%p A384498 select(q, [$1..20000])[];
%t A384498 Join[{1},Select[Range[16600],SquareFreeQ[#]&&MemberQ[Total/@Subsets[First/@FactorInteger[#]],Total[First/@FactorInteger[#]]/2]&]] (* _James C. McMahon_, Jun 02 2025 *)
%Y A384498 Intersection of A005117 and A221054.
%Y A384498 Cf. A071141, A071142, A071312.
%K A384498 nonn
%O A384498 1,2
%A A384498 _Alois P. Heinz_, May 31 2025