Basis for code in A075949.

Terms

a(0) =2047a(1) =129055a(2) =932067a(3) =3299692a(4) =5548725a(5) =25323961a(6) =42250958a(7) =202390343a(8) =806394569a(9) =1409681880a(10) =2492481691a(11) =12894763567a(12) =21811487392a(13) =103089080516a(14) =176362268954a(15) =824702327536