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 A341353 #12 Feb 15 2021 22:50:20
%S A341353 0,0,1,0,0,0,0,1,2,0,0,0,0,0,1,0,0,0,0,2,1,0,0,1,0,0,0,0,1,0,0,0,1,0,
%T A341353 3,0,0,1,1,0,0,0,0,0,3,0,0,1,0,0,0,0,0,2,0,1,0,0,0,0,1,0,2,0,1,0,0,0,
%U A341353 0,0,0,0,0,0,0,0,0,0,0,1,1,0,1,1,0,3,3,0,2,2,0,0,2,0,0,0,0,0,1,0,2,0,0
%N A341353 Greatest k such that 3^k divides A156552(n); the 3-adic valuation of A156552(n).
%H A341353 Antti Karttunen, <a href="/A341353/b341353.txt">Table of n, a(n) for n = 2..65539</a>
%H A341353 <a href="/index/Pri#prime_indices">Index entries for sequences computed from indices in prime factorization</a>
%F A341353 a(n) = A007949(A156552(n)).
%F A341353 a(p) = 0 for all primes p.
%F A341353 a(n^2) > 0 for all n >= 2.
%F A341353 a(n) > 0 iff A329903(n) = 0.
%o A341353 (PARI)
%o A341353 A007949(n) = valuation(n,3);
%o A341353 A156552(n) = { my(f = factor(n), p2 = 1, res = 0); for(i = 1, #f~, p = 1 << (primepi(f[i, 1]) - 1); res += (p * p2 * (2^(f[i, 2]) - 1)); p2 <<= f[i, 2]); res };
%o A341353 A341353(n) = A007949(A156552(n));
%Y A341353 Cf. A007949, A156552, A329609 (positions of nonzeros), A329903, A341354 (even bisection), A341355.
%Y A341353 Cf. also A055396 (the 2-adic valuation + 1), A292251.
%K A341353 nonn
%O A341353 2,9
%A A341353 _Antti Karttunen_, Feb 14 2021