0,1

4-almost prime analog of A005596.

The logarithm is -sum_{s>=2} sum_{j=1..floor[s/(1+r)]} binomial(s-r*j-1,j-1)*P_4(s)/j at r=1, where P_k(s) are the k-almost prime zeta functions of arXiv:0803.0900.

0.989628867166427665504.. = (1-1/240)*(1-1/552)*...

Sequence in context: A163930 A157371 A159590 this_sequence A116695 A109940 A010549

Adjacent sequences: A146481 A146482 A146483 this_sequence A146485 A146486 A146487

nonn,cons,less

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