G.f.: A(x) = Sum_{n>=0} x^n/(1-x)^A038722(n), where A038722(n) = floor(sqrt(2*n)+1/2)^2 - n + 1.

Terms

a(0) =1a(1) =1a(2) =2a(3) =5a(4) =10a(5) =21a(6) =47a(7) =103a(8) =217a(9) =451a(10) =951a(11) =2047a(12) =4439a(13) =9548a(14) =20231a(15) =42355a(16) =88373a(17) =185343a(18) =392297a(19) =836502a(20) =1787158a(21) =3803651a(22) =8035998a(23) =16846041a(24) =35121641a(25) =73103052a(26) =152493454a(27) =319600236a(28) =673256721a(29) =1423293503