A377512 - OEIS

A377512

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

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, 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, 1, 1, 1, 5, 1, 1, 1, 1, 1, 1, 1, 2, 2, 3, 1, 2, 1, 2

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OFFSET

1,1

COMMENTS

See A377120 for a guide to related sequences.

LINKS

Robert Israel, Table of n, a(n) for n = 1..10000

EXAMPLE

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

MAPLE

f:= proc(p) local x, i;

x:= p;