A204911 - OEIS

%I #17 Jun 25 2024 11:24:51

%S 5,5,5,7,7,5,5,5,5,7,7,5,5,5,7,7,7,5,5,11,5,7,7,5,11,5,5,13,13,7,5,5,

%T 5,7,13,5,5,5,5,7,7,5,11,17,7,7,7,5,5,11,5,7,7,5,17,5,13,13,13,7,5,5,

%U 5,7,7,5,5,5,11,13,7,7,5,5,7,7,13,5,5,17,5,7,7,5,11,11,5,13,13,7,11,5,5

%N The prime q>=5 such that n divides p-q, where p>q is the least prime for which such a prime q exists.

%C For a guide to related sequences, see A204892.

%H Robert Israel, <a href="/A204911/b204911.txt">Table of n, a(n) for n = 1..10000</a>

%p f:= proc(n) local V,q,r;

%p   V:= Array(0..n-1); q:= 4;

%p   do

%p    q:= nextprime(q);

%p    r:= q mod n;

%p    if V[r] = 0 then V[r]:= q

%p    else return V[r]

%p    fi

%p   od

%p end proc:

%p map(f, [$1..100]); # _Robert Israel_, Jul 24 2018

%t (See the program at A204908.)

%o (Python)

%o from sympy import nextprime

%o def a(n):

%o     V, q = [0 for _ in range(n)], 4

%o     while True:

%o         q = nextprime(q)

%o         r = q%n

%o         if V[r] == 0: V[r] = q

%o         else: return int(V[r])

%o print([a(n) for n in range(1, 94)]) # _Michael S. Branicky_, Jun 25 2024 after _Robert Israel_

%Y Cf. A204908, A204900, A204892.

%K nonn

%O 1,1

%A _Clark Kimberling_, Jan 20 2012

%E More terms from _Robert G. Wilson v_, Jul 24 2018