Number of solutions to 2*k_1 + 3*k_2 + ... + prime(n)*k_n = 1, where k_i are from {-1,0,1}, i=1..n.

Terms

a(0) =0a(1) =0a(2) =1a(3) =1a(4) =3a(5) =8a(6) =18a(7) =39a(8) =95a(9) =233a(10) =565a(11) =1440a(12) =3640a(13) =9409a(14) =24957a(15) =66699a(16) =177931a(17) =475584a(18) =1292985a(19) =3517163a(20) =9636135a(21) =26675682a(22) =73847316a(23) =205379443a(24) =571621138a(25) =1588186858a(26) =4435778209a(27) =12474517743a(28) =35194193531a(29) =99781874834