Year-end appeal: Please make a donation to the OEIS Foundation to support ongoing development and maintenance of the OEIS. We are now in our 61st year, we have over 378,000 sequences, and we’ve reached 11,000 citations (which often say “discovered thanks to the OEIS”).
%I #10 Mar 15 2014 05:29:25
%S 1,1,4,1,1,2,1,2,3,1,1,2,3,1,6,1,1,2,1,1,1,3,2,1,5,2,1,4,2,1,3,1,2,1,
%T 1,1,3,1,4,1,2,1,2,5,1,1,1,2,4,1,3,1,2,1,2,1,2,1,4,1,1,3,1,2,1,1,3,2,
%U 1,2,1,3,1,1,8,2,1,1,2,1,2,3,1,5,1,2,3,1,2,1,4,1,1,2,6,1,2,1,3,1
%N Exponent of 2 in prime factorization (i.e., 2-adic valuation) of odd nonprimes A014076(n) + 1.
%C Sequence is counterpart to A023512, i.e., merging these two sequences gives the ruler function A001511.
%H K. G. Stier, <a href="/A239114/b239114.txt">Table of n, a(n) for n = 1..7739</a>
%F a(n) = A001511((A014076(n)+1)/2)
%e a(13) = 3, because the 13th odd nonprime is 55, and the largest power of 2 dividing 55+1 is 3.
%o (PARI) lista(nn) = {forstep(n=1, nn, 2, if (! isprime(n), print1(valuation(n+1, 2), ", ")););} \\ _Michel Marcus_, Mar 13 2014
%Y Cf. A023512, A001511, A014076.
%K nonn
%O 1,3
%A _K. G. Stier_, Mar 10 2014