0,1

Semiprime analog of A065414.

The logarithm is -sum_{s>=2} sum_{j=1..floor[s/(1+r)]} binomial(s-r*j-1,j-1)*P_2(s)/j at r=2, where P_k(s) are the k-almost prime zeta functions of arXiv:0803.0900.

0.969932325001525316214920... = (1-1/48)*(1-1/180)*(1-1/648)*(1-1/900)*..

Sequence in context: A019711 A010545 A019790 this_sequence A137907 A070164 A063602

Adjacent sequences: A146483 A146484 A146485 this_sequence A146487 A146488 A146489

nonn,cons,less

R. J. Mathar (mathar(AT)strw.leidenuniv.nl), Feb 13 2009