A239114 Exponent of 2 in prime factorization (i.e., 2-adic valuation) of odd nonprimes A014076(n) + 1.

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, 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, 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

Offset: 1

Author

K. G. Stier, Mar 10 2014

Keywords

• nonn

Comments

Sequence is counterpart to A023512, i.e., merging these two sequences gives the ruler function A001511.

Examples

			a(13) = 3, because the 13th odd nonprime is 55, and the largest power of 2 dividing 55+1 is 3.
		

Links

• K. G. Stier, Table of n, a(n) for n = 1..7739

Crossrefs

Cf. A023512, A001511, A014076.

Programs

PARI

lista(nn) = {forstep(n=1, nn, 2, if (! isprime(n), print1(valuation(n+1, 2), ", ")););} \\ Michel Marcus, Mar 13 2014

Formula

a(n) = A001511((A014076(n)+1)/2)