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 A332202 #4 Mar 07 2020 02:11:01
%S A332202 0,1,2,1,2,1,3,1,2,1,2,1,3,1,2,1,2,1,4,1,2,1,2,1,3,1,2,1,2,1,3,1,2,1,
%T A332202 2,1,4,1,2,1,2,1,3,1,2,1,2,1,3,1,2,1,2,1,5,1,2,1,2,1,3,1,2,1,2,1,3,1,
%U A332202 2,1,2,1,4,1,2,1,2,1,3,1,2,1,2,1,3,1,2,1,2,1,4,1,2,1,2,1,3,1,2,1
%N A332202 Largest k >= 0 such that 3^k divides 2^(2^n-1) + 1.
%C A332202 Behaves like a mixture of 2-adic and 3-adic ruler function, cf. formula.
%F A332202 For all n > 0, a(2n-1) = 1; a(2n) = 2 + A007949(n) = 1 + A051064(n).
%e A332202 a(0) = 0 since 2^(2^0-1) + 1 = 2^0 + 1 = 2 is not divisible by 3.
%e A332202 a(1) = 1 since 2^(2^1-1) + 1 = 2^1 + 1 = 3 is divisible just once by 3.
%e A332202 a(2) = 2 since 2^(2^2-1) + 1 = 2^3 + 1 = 9 is divisible by 3^2.
%e A332202 a(3) = 1 since 2^(2^4-1) + 1 = 2^15 + 1 = 32769 is divisible only once by 3.
%o A332202 (PARI) apply( {A332202(n)=if(bittest(n,0), 1, n, valuation(n\2,3)+2)}, [0..99])
%Y A332202 Cf. A007949, A051064, A001511 (2-adic ruler)
%K A332202 nonn
%O A332202 0,3
%A A332202 _M. F. Hasler_, Mar 05 2020