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 A366308 #7 Oct 07 2023 08:47:38 %S A366308 1,2,2,1,2,4,2,2,1,4,2,2,2,4,4,2,2,2,2,2,4,4,2,4,1,4,2,2,2,8,2,4,4,4, %T A366308 4,1,2,4,4,4,2,8,2,2,2,4,2,4,1,2,4,2,2,4,4,4,4,4,2,4,2,4,2,2,4,8,2,2, %U A366308 4,8,2,2,2,4,2,2,4,8,2,4,2,4,2,4,4,4,4 %N A366308 The number of infinitary divisors of n that are terms of A366242. %H A366308 Amiram Eldar, <a href="/A366308/b366308.txt">Table of n, a(n) for n = 1..10000</a> %F A366308 Multiplicative with a(p^e) = 2^A139351(e). %F A366308 a(n) = 2^A366246(n). %F A366308 a(n) = A037445(n)/A366309(n). %F A366308 a(n) = A037445(A366244(n)). %F A366308 a(n) >= 1, with equality if and only if n is in A366243. %F A366308 a(n) <= A037445(n), with equality if and only if n is in A366242. %t A366308 s[0] = 0; s[n_] := s[n] = s[Floor[n/4]] + If[OddQ[Mod[n, 4]], 1, 0]; f[p_, e_] := 2^s[e]; a[1] = 1; a[n_] := Times @@ f @@@ FactorInteger[n]; Array[a, 100] %o A366308 (PARI) s(e) = if(e > 3, s(e\4)) + e%2 \\ after _Charles R Greathouse IV_ at A139351 %o A366308 a(n) = vecprod(apply(x -> 2^s(x), factor(n)[, 2])); %Y A366308 Cf. A037445, A139351, A366242, A366243, A366244, A366246, A366309. %K A366308 nonn,easy,mult %O A366308 1,2 %A A366308 _Amiram Eldar_, Oct 06 2023