a(n) = A076795(n) - 1.

Terms

a(0) =0a(1) =1a(2) =4a(3) =19a(4) =124a(5) =1069a(6) =11464a(7) =146599a(8) =2173624a(9) =36633049a(10) =691362124a(11) =14440672699a(12) =330674815924