A204904 - OEIS

%I #25 Mar 14 2018 17:41:44

%S 2,2,6,4,10,6,14,8,18,10,22,12,26,14,30,16,34,18,38,20,42,22,46,24,50,

%T 26,54,28,58,30,62,32,66,34,70,36,74,38,78,40,82,42,86,44,90,46,94,48,

%U 98,50,102,52,106,54,110,56,114,58,118,60,122,62,126,64,130

%N p(n)-q(n), where (p(n), q(n)) is the least pair of odd primes for which n divides p(n)-q(n).

%C This sequence agrees with A109043 for 0<n<=65; what about all larger n?

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

%C Sequence agrees with A109043 at least up to 6400. - _Michel Marcus_, Mar 14 2018

%C If Polignac's conjecture is true, then this is a duplicate of A109043. - _Robert Israel_, Mar 14 2018

%H Wikipedia, <a href="https://en.wikipedia.org/wiki/Polignac%27s_conjecture">Polignac's conjecture</a>

%e 1 = (5-3)/2=(7-3)/4=(13-3)/6=(11-3)/8=...

%e 2 = (5-3)/1=(11-5)/3=(7-3)/5=(17-3)/7=...

%t (See the program at A204900.)

%o (PARI) a(n) = {forprime(p=5,,forprime(q=3, p-1, d = p-q; if ((d % n) == 0, return (d));););} \\ _Michel Marcus_, Mar 14 2018

%Y Cf. A066043, A109043, A204900, A204892, A210530.

%K nonn

%O 1,1

%A _Clark Kimberling_, Jan 20 2012