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 A353509 #9 Apr 29 2022 15:55:07 %S A353509 0,0,0,0,0,2,0,0,0,2,0,4,0,2,2,0,0,4,0,4,2,2,0,7,0,2,0,4,0,9,0,0,2,2, %T A353509 2,8,0,2,2,7,0,9,0,4,4,2,0,10,0,4,2,4,0,7,2,7,2,2,0,16,0,2,4,0,2,9,0, %U A353509 4,2,9,0,14,0,2,4,4,2,9,0,10,0,2,0,16,2,2,2,7,0,16,2,4,2,2,2,15,0,4,4,8,0,9 %N A353509 a(n) = A353379(n) - A001222(n). %C A353509 The difference of A258851 (primepi-based arithmetic derivative) and A056239 (sum of prime indices with multiplicity) applied to A181819, the prime shadow of n. %H A353509 Antti Karttunen, <a href="/A353509/b353509.txt">Table of n, a(n) for n = 1..65537</a> %H A353509 <a href="/index/Eu#epf">Index entries for sequences computed from exponents in factorization of n</a> %F A353509 a(n) = A278510(A181819(n)) = A353379(n) - A001222(n). %o A353509 (PARI) %o A353509 A181819(n) = factorback(apply(e->prime(e),(factor(n)[,2]))); %o A353509 A258851(n) = (n*sum(i=1, #n=factor(n)~, n[2, i]*primepi(n[1, i])/n[1, i])); \\ From A258851 %o A353509 A353509(n) = (A258851(A181819(n))-bigomega(n)); %Y A353509 Cf. A001222, A056239, A181819, A258851, A278510, A353379. %K A353509 nonn %O A353509 1,6 %A A353509 _Antti Karttunen_, Apr 29 2022