Convolution of odd numbers and A000201.

Terms

a(0) =1a(1) =6a(2) =18a(3) =40a(4) =76a(5) =129a(6) =202a(7) =298a(8) =420a(9) =572a(10) =757a(11) =978a(12) =1239a(13) =1543a(14) =1893a(15) =2292a(16) =2743a(17) =3250a(18) =3816a(19) =4444a(20) =5137a(21) =5898a(22) =6731a(23) =7639a(24) =8625a(25) =9693a(26) =10846a(27) =12087a(28) =13419a(29) =14845