A309067 - OEIS

%I #10 Jul 16 2019 11:52:00

%S -1,2,2,3,3,4,3,5,2,5,3,5,3,2,5,3,5,3,5,-1,8,3,5,7,-1,5,4,-1,4,12,3,2,

%T 5,-1,11,3,4,3,5,7,-1,-1,3,3,4,10,-1,5,2,-1,3,-1,5,-1,-1,-1,2,-1,4,-1,

%U 5,-1,2,-1,4,3,-1,5,6,5,6,-1,6,-1,5,-1,4,7,3,-1,5,-1,-1,-1,2,6,5,5,3,4

%N Index of A053319(n) in A014574; -1 if it doesn't exist.

%t ind[v_, e_] := If[Length[(p = Position[v, _?(# == e &)])] == 0, -1, p[[1]]]; tpmidQ[n_] := And @@ PrimeQ[n + {-1, 1}]; tp = Select[Range[10^4], tpmidQ]; d = Differences[tp]; ind[tp, #] & /@ d // Flatten (* _Amiram Eldar_, Jul 12 2019 *)

%Y Cf. A014574, A053319, A309066.

%K sign

%O 1,2

%A _Dmitry Kamenetsky_, Jul 10 2019