Smallest prime p such that tau(p-1) + tau(p+1) is n, or 0 if no such number exists.

Terms

a(0) =0a(1) =0a(2) =2a(3) =0a(4) =3a(5) =0a(6) =5a(7) =7a(8) =0a(9) =11a(10) =17a(11) =19a(12) =37a(13) =29a(14) =0a(15) =41a(16) =101a(17) =79a(18) =0a(19) =71a(20) =197a(21) =179a(22) =401a(23) =199a(24) =2917a(25) =181a(26) =577a(27) =239a(28) =3137a(29) =883