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 A380888 #20 Apr 25 2025 18:18:26 %S A380888 2,9,75,625,1029,1365,8575,11375,24843,32955,73815,117649,156065, %T A380888 207025,274625,483153,599781,615125,866481,1008273,1252815,1337505, %U A380888 1343433,1553937,1782105,1955085,2061345,2840383,3051015,3432165,3737085,3767855,4026275,4998175 %N A380888 Integers k such that k = Sum k/(p_i + j), where p_i are the prime factors of k (with multiplicity). Case j = -1. %C A380888 2 is the only even term. - _Chai Wah Wu_, Apr 24 2025 %H A380888 Robert Israel, <a href="/A380888/b380888.txt">Table of n, a(n) for n = 1..213</a> %e A380888 73815 = 3*5*7*19*37 = 73815/(3-1) + 73815/(5-1) + 73815/(7-1) + 73815/(19-1) + 73815/(37-1); %e A380888 599781 = 3*7*13^4 = 599781/(3-1) + 599781/(7-1) + 599781*4/(13-1). %p A380888 with(numtheory): P:=proc(q,h) local k,n,v; v:=[]; %p A380888 for n from 1 to q do if n=add(n*k[2]/(k[1]+h),k=ifactors(n)[2]) then v:=[op(v),n]; fi; %p A380888 od; op(v); end: P(4998175,-1); %Y A380888 Cf. A380889, A380900, A380901, A380923-A380928. %Y A380888 Contains A036878. %K A380888 nonn %O A380888 1,1 %A A380888 _Paolo P. Lava_, Feb 07 2025