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 A374780 #4 Jul 19 2024 14:28:34
%S A374780 10854718875,12131744625,13408770375,18091198125,19538493975,
%T A374780 20219574375,21070924875,22347950625,22915517625,23880381525,
%U A374780 24902002125,25327677375,28307404125,28733079375,29462808375,32564156625,35118208125,36395233875,39800635875,40226311125
%N A374780 Odd terms in A245214.
%C A374780 Odd numbers whose divisors have a mean abundancy index that is larger than 2.
%C A374780 The odd terms in A245214 are relatively rare: a(1) = A245214(276918705).
%C A374780 The least term that is not divisible by 3 is 26115176669245401228259189019322202117310546875.
%e A374780 10854718875 is a term since it is odd and A374777(10854718875) / A374778(10854718875) = 11975203 / 5955950 = 2.0106... > 2.
%t A374780 f[p_, e_] := ((e+1)*p^2 - (e+2)*p + p^(-e))/((e+1)*(p-1)^2); s[1] = 1; s[n_] := Times @@ f @@@ FactorInteger[n]; seq[kmax_] := Module[{v = {}}, Do[If[s[k] > 2, AppendTo[v, k]], {k, 1, kmax, 2}]; v]; seq[2*10^10]
%o A374780 (PARI) is(k) = if(!(k % 2), 0, my(f = factor(k)); prod(i = 1, #f~, p=f[i,1]; e=f[i,2]; (-2*p - e*p + p^2 + e*p^2 + p^(-e))/((e + 1)*(p - 1)^2)) > 2);
%Y A374780 Subsequence of A245214.
%Y A374780 Cf. A005231, A374777, A374778.
%K A374780 nonn
%O A374780 1,1
%A A374780 _Amiram Eldar_, Jul 19 2024