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 A371090 #9 Mar 31 2024 14:03:34
%S A371090 0,1,1,1,1,2,1,2,1,2,1,2,1,2,2,1,1,2,1,2,2,2,1,3,1,2,2,2,1,3,1,2,2,2,
%T A371090 2,2,1,2,2,3,1,3,1,2,2,2,1,2,1,2,2,2,1,3,2,3,2,2,1,3,1,2,2,1,2,3,1,2,
%U A371090 2,3,1,3,1,2,2,2,2,3,1,2,1,2,1,3,2,2,2,3,1,3,2,2,2,2,2,3,1,2,2,2,1,3,1,3,3,2,1,3,1,3,2,2,1,3,2,2,2,2,2,4,1,2,2,2,2,3,1,2
%N A371090 Additive with a(p^1) = 1, a(p^e) = a(A276086(e)) for e > 1, where A276086 is the primorial base exp-function.
%C A371090 Used to construct A371091.
%H A371090 Antti Karttunen, <a href="/A371090/b371090.txt">Table of n, a(n) for n = 1..65537</a>
%H A371090 <a href="/index/Eu#epf">Index entries for sequences computed from exponents in factorization of n</a>
%F A371090 Additive with a(p^1) = 1, a(p^e) = A371091(e) for e > 1.
%F A371090 For all n >= 1, A001221(n) <= a(n) <= A001222(n).
%o A371090 (PARI)
%o A371090 A276086(n) = { my(m=1, p=2); while(n, m *= (p^(n%p)); n = n\p; p = nextprime(1+p)); (m); };
%o A371090 A371090(n) = vecsum(apply(e->if(1==e,1,A371090(A276086(e))),factor(n)[, 2]));
%Y A371090 Cf. A001221, A001222, A276086, A371091.
%Y A371090 Differs from A064547 for the first time at n=63, where a(64) = 1, while A064547(64) = 2.
%Y A371090 Differs from A058061 for the first time at n=128, where a(128) = 2, while A058061(128) = 3.
%K A371090 nonn
%O A371090 1,6
%A A371090 _Antti Karttunen_, Mar 31 2024