a(n) is the solution to the postage stamp problem with 5 denominations and n stamps.

Terms

a(0) =5a(1) =16a(2) =36a(3) =70a(4) =126a(5) =216a(6) =345a(7) =512a(8) =797a(9) =1055a(10) =1475a(11) =2047a(12) =2659a(13) =3403a(14) =4422a(15) =5629a(16) =6865a(17) =8669a(18) =10835a(19) =12903a(20) =15785a(21) =18801a(22) =22456a(23) =26469a(24) =31108a(25) =36949a(26) =42744a(27) =49436a(28) =57033a(29) =66771