Duplicate of A023856.

Terms

a(0) =2a(1) =3a(2) =10a(3) =13a(4) =28a(5) =34a(6) =60a(7) =70a(8) =110a(9) =125a(10) =182a(11) =203a(12) =280a(13) =308a(14) =408a(15) =444a(16) =570a(17) =615a(18) =770a(19) =825