1,1

Table of n, a(n) for n=1..74.

a(n)=binomial ( (A000120(s)+A023416(s)), A000120(s) ), where s=semiprime(n).

a(1)=3 because (100,010,001) where semiprime(1)=3=100 (in base 2).

Cf. A177687.

Sequence in context: A038167 A307967 A131077 * A271668 A072464 A262871

Adjacent sequences: A175517 A175518 A175519 * A175521 A175522 A175523

nonn,base

Juri-Stepan Gerasimov, Jun 05 2010

a(56) corrected by R. J. Mathar, Jun 07 2010

approved