a(0) = 1, a(n+1) = a(n) + next prime larger than a(n).

Terms

a(0) =1a(1) =3a(2) =8a(3) =19a(4) =42a(5) =85a(6) =174a(7) =353a(8) =712a(9) =1431a(10) =2864a(11) =5743a(12) =11492a(13) =22989a(14) =45982a(15) =91971a(16) =183968a(17) =367939a(18) =735888a(19) =1471789a(20) =2943596a(21) =5887195a(22) =11774408a(23) =23548837a(24) =47097690a(25) =94195387a(26) =188390808a(27) =376781617a(28) =753563240a(29) =1507126509