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 A366742 #10 Oct 21 2023 01:50:12 %S A366742 1,2,2,3,2,4,2,2,3,4,2,6,2,4,4,5,2,6,2,6,4,4,2,4,3,4,2,6,2,8,2,2,4,4, %T A366742 4,9,2,4,4,4,2,8,2,6,6,4,2,10,3,6,4,6,2,4,4,4,4,4,2,12,2,4,6,3,4,8,2, %U A366742 6,4,8,2,6,2,4,6,6,4,8,2,10,5,4,2,12,4,4 %N A366742 The number of divisors of the least coreful infinitary divisor of n. %C A366742 The sum of divisors of the least coreful infinitary divisor of n is A366744(n). %H A366742 Amiram Eldar, <a href="/A366742/b366742.txt">Table of n, a(n) for n = 1..10000</a> %F A366742 a(n) = A000005(A365296(n)). %F A366742 a(n) = A000005(n) if and only if n is in A138302. %F A366742 Multiplicative with a(p^e) = A006519(e) + 1. %t A366742 f[p_, e_] := 2^IntegerExponent[e, 2] + 1; a[1] = 1; a[n_] := Times @@ f @@@ FactorInteger[n]; Array[a, 100] %o A366742 (PARI) a(n) = vecprod(apply(x -> 2^valuation(x, 2) + 1, factor(n)[, 2])); %Y A366742 Cf. A000005, A006519, A138302, A365296, A366743, A366744. %K A366742 nonn,easy,mult %O A366742 1,2 %A A366742 _Amiram Eldar_, Oct 19 2023