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 A341354 #15 Mar 11 2021 03:23:18
%S A341354 0,1,0,0,2,0,0,1,0,0,1,0,0,0,1,0,1,3,0,1,0,0,3,0,0,0,0,0,0,0,1,2,1,0,
%T A341354 0,0,0,0,0,0,1,1,0,3,2,0,2,0,0,1,2,0,0,0,0,0,0,0,1,1,0,0,0,0,0,0,1,1,
%U A341354 1,0,0,1,2,0,0,0,4,1,0,1,0,0,1,0,0,0,0,0,0,0,0,1,1,0,0,0,1,2,1,0,0,0,4,0,0
%N A341354 Greatest k such that 3^k divides A156552(2*n); number of trailing 1-digits in the ternary expansion of A156552(n).
%C A341354 The 3-adic valuation of A156552(2*n).
%H A341354 Antti Karttunen, <a href="/A341354/b341354.txt">Table of n, a(n) for n = 1..65539</a>
%H A341354 <a href="/index/Pri#prime_indices">Index entries for sequences computed from indices in prime factorization</a>
%F A341354 a(n) = A341353(2*n) = A007949(A156552(2*n)) = A007949(1+(2*A156552(n))).
%F A341354 For all n >= 1, a(A000040(2*n)) = a(n^2) = 0.
%o A341354 (PARI)
%o A341354 A007949(n) = valuation(n,3);
%o A341354 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 A341354 A341354(n) = A007949(A156552(2*n));
%Y A341354 Even bisection of A341353.
%Y A341354 Cf. A000040, A007949, A156552, A341355.
%Y A341354 Cf. A329604 (positions of nonzero terms).
%K A341354 nonn
%O A341354 1,5
%A A341354 _Antti Karttunen_, Feb 14 2021