Sums of groups in A075643.

Terms

a(0) =2a(1) =9a(2) =16a(3) =55a(4) =78a(5) =112a(6) =232a(7) =342a(8) =420a(9) =605a(10) =852a(11) =1053a(12) =1330a(13) =1650a(14) =2144a(15) =2601a(16) =3168a(17) =3534a(18) =4420a(19) =5229a(20) =5984a(21) =6670a(22) =7440a(23) =8950a(24) =10478a(25) =11232a(26) =12712a(27) =13775a(28) =15510a(29) =17236