Divide primes in groups with 2n+1 elements and add together.

Terms

a(0) =2a(1) =15a(2) =83a(3) =281a(4) =679a(5) =1367a(6) =2461a(7) =4005a(8) =6223a(9) =9017a(10) =12755a(11) =17281a(12) =22967a(13) =29597a(14) =37793a(15) =47229a(16) =57993a(17) =70957a(18) =85343a(19) =101777a(20) =119469a(21) =141079a(22) =163313a(23) =188201a(24) =216203a(25) =247203a(26) =280897a(27) =316551a(28) =355905a(29) =398825