A377512 - OEIS

%I #4 Nov 13 2024 17:26:20

%S 4,3,2,5,3,1,4,1,2,3,2,3,1,2,1,1,2,2,1,1,2,1,3,2,1,3,1,4,3,1,2,1,1,1,

%T 3,1,3,1,1,2,2,2,1,1,2,3,1,1,2,1,2,2,1,2,1,1,1,1,7,1,1,2,1,3,2,1,2,1,

%U 1,1,1,5,1,1,1,1,1,1,1,2,2,3,1,2,1,2

%N a(n) = number of iterations of x -> 2 x - 3 to reach a nonprime, starting with  prime(n).

%C See A377120 for a guide to related sequences.

%e prime(3) = 5 -> 7 -> 11 -> 19 -> 35 = 5*7, so a(1) = 4.

%t Table[p = Prime[n]; c = 1; While[p = 2*p + 7; PrimeQ[p], c++]; c, {n, 200}]

%Y Cf. A377120, A377510, A377511, A377513, A377514.

%K nonn

%O 1,1

%A _Clark Kimberling_, Nov 05 2024