a(n) = Min{ q prime | nextprime(q) - q - 1 = prime(n)}, or 0 if none exist.

Terms

a(0) =7a(1) =23a(2) =89a(3) =199a(4) =113a(5) =523a(6) =887a(7) =1669a(8) =4297a(9) =5591a(10) =30593a(11) =16141a(12) =15683a(13) =28229a(14) =35617a(15) =43331a(16) =34061a(17) =134513a(18) =31397a(19) =404597a(20) =542603a(21) =461717a(22) =404851a(23) =604073a(24) =1444309a(25) =1388483a(26) =2238823a(27) =1468277a(28) =492113a(29) =3851459