Convolution of A000009 and A000290.

Terms

a(0) =0a(1) =1a(2) =5a(3) =14a(4) =31a(5) =60a(6) =106a(7) =176a(8) =279a(9) =426a(10) =631a(11) =912a(12) =1291a(13) =1795a(14) =2457a(15) =3317a(16) =4424a(17) =5837a(18) =7626a(19) =9875a(20) =12684a(21) =16171a(22) =20476a(23) =25764a(24) =32228a(25) =40094a(26) =49626a(27) =61131a(28) =74966a(29) =91545