a(n) = prime(2^n) - n^2.

Terms

a(0) =2a(1) =3a(2) =10a(3) =37a(4) =106a(5) =275a(6) =670a(7) =1555a(8) =3590a(9) =8061a(10) =17742a(11) =38729a(12) =83848a(13) =180307a(14) =385868a(15) =821385a(16) =1742248a(17) =3680807a(18) =7753716a(19) =16289647a(20) =34135588a(21) =71378085a(22) =148947610a(23) =310247665