p-INVERT of the positive integers, where p(S) = (1 - S)^2.

Terms

a(0) =2a(1) =7a(2) =22a(3) =67a(4) =200a(5) =588a(6) =1708a(7) =4913a(8) =14018a(9) =39725a(10) =111922a(11) =313752a(12) =875702a(13) =2434747a(14) =6746350a(15) =18636343a(16) =51340988a(17) =141089508a(18) =386857888a(19) =1058572325a(20) =2891193242a(21) =7882921697a(22) =21458980582a(23) =58330331952a(24) =158339542250a(25) =429274563823