Sum of terms in n-th group in A075352.

Terms

a(0) =1a(1) =2a(2) =7a(3) =11a(4) =24a(5) =33a(6) =58a(7) =74a(8) =115a(9) =140a(10) =201a(11) =237a(12) =273a(13) =364a(14) =413a(15) =532a(16) =596a(17) =747a(18) =828a(19) =1015a(20) =1115a(21) =1342a(22) =1463a(23) =1734a(24) =1878a(25) =2022a(26) =2353a(27) =2522a(28) =2905a(29) =3101