a(n) = 1 + Sum(prime(i)*(2*i-1): 1<=i<=n).

Terms

a(0) =3a(1) =12a(2) =37a(3) =86a(4) =185a(5) =328a(6) =549a(7) =834a(8) =1225a(9) =1776a(10) =2427a(11) =3278a(12) =4303a(13) =5464a(14) =6827a(15) =8470a(16) =10417a(17) =12552a(18) =15031a(19) =17800a(20) =20793a(21) =24190a(22) =27925a(23) =32108a(24) =36861a(25) =42012a(26) =47471a(27) =53356a(28) =59569a(29) =66236