Divide natural numbers in groups with prime(n) elements and add together.

Terms

a(0) =1a(1) =9a(2) =35a(3) =91a(4) =242a(5) =442a(6) =833a(7) =1273a(8) =2024a(9) =3306a(10) =4464a(11) =6586a(12) =8897a(13) =11137a(14) =14288a(15) =18762a(16) =24190a(17) =28670a(18) =35778a(19) =42813a(20) =49275a(21) =59329a(22) =69056a(23) =81702a(24) =98067a(25) =112110a(26) =124836a(27) =140919a(28) =155325a(29) =173568