Smallest a(n) such that a(n) n's plus a(n) is prime, or 0 if no such a(n) exists.

Terms

a(0) =1a(1) =1a(2) =140a(3) =1a(4) =0a(5) =1a(6) =2a(7) =0a(8) =2a(9) =1a(10) =0a(11) =1a(12) =4a(13) =0a(14) =4a(15) =1a(16) =0a(17) =1a(18) =4a(19) =0a(20) =0a(21) =1a(22) =0a(23) =23a(24) =4a(25) =0a(26) =2a(27) =1a(28) =0a(29) =1