Convolution of A000041 and A237271.

Terms

a(0) =1a(1) =2a(2) =5a(3) =8a(4) =15a(5) =23a(6) =38a(7) =56a(8) =87a(9) =125a(10) =183a(11) =256a(12) =363a(13) =498a(14) =688a(15) =926a(16) =1252a(17) =1661a(18) =2207a(19) =2889a(20) =3786a(21) =4900a(22) =6339a(23) =8122a(24) =10397a(25) =13201a(26) =16741a(27) =21082a(28) =26510a(29) =33142