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 A374217 #6 Jul 02 2024 18:50:07 %S A374217 0,1,0,0,0,0,1,1,0,0,0,0,2,0,0,0,0,0,2,0,0,0,2,0,1,2,0,0,0,0,0,0,0,1, %T A374217 0,0,1,0,0,0,1,0,1,0,0,0,0,0,1,0,0,0,0,0,0,0,0,0,1,0,1,0,1,2,0,0,1,0, %U A374217 0,0,1,0,1,0,0,2,2,0,0,1,0,0,0,0,2,0,0,0,0,0,3,0,0,1,0,0,0,0,0,0,0,0,0,1,0,0,0,0,2,0,1,0,1,0,1,0,0,1,0,0,2 %N A374217 The 3-adic valuation of sopfr(n), where sopfr is the sum of prime factors with repetition, A001414. %H A374217 Antti Karttunen, <a href="/A374217/b374217.txt">Table of n, a(n) for n = 2..100000</a> %F A374217 a(n) = A007949(A001414(n)). %o A374217 (PARI) %o A374217 A001414(n) = ((n=factor(n))[, 1]~*n[, 2]); %o A374217 A374217(n) = valuation(A001414(n), 3); %Y A374217 Cf. A001414, A007949, A289142 (gives the indices of nonzero terms here, after its initial 1), A373371 %Y A374217 Cf. also A374207, A374216. %K A374217 nonn %O A374217 2,13 %A A374217 _Antti Karttunen_, Jul 02 2024