A023151 - OEIS

%I #25 Feb 11 2021 22:54:32

%S 1,2,10,11,35,37,80,100364,251711,251717,251731,251735,251741,251770,

%T 4124456,4124582,27067096,27067520,69709706,69709717,69709723,

%U 69709868,69709931,69709933,465769825,465769826,465769831,1208198548,8179002130

%N Numbers k such that prime(k) == 9 (mod k).

%H Giovanni Resta, <a href="/A023151/b023151.txt">Table of n, a(n) for n = 1..46</a>

%t NextPrim[n_] := Block[{k = n + 1}, While[ !PrimeQ[k], k++ ]; k]; p = 1; Do[ If[ Mod[p = NextPrim[p], n] == 9, Print[n]], {n, 1, 10^9}] (* _Robert G. Wilson v_, Feb 18 2004 *)

%o (Sage)

%o def A023151(max) :

%o     terms = []

%o     p = 2

%o     for n in range(1, max+1) :

%o         if (p - 9) % n == 0 : terms.append(n)

%o         p = next_prime(p)

%o     return terms

%o # _Eric M. Schmidt_, Feb 05 2013

%Y Cf. A092051, A023143, A023144, A023145, A023146, A023147, A023148, A023149, A023150, A023152.

%K nonn

%O 1,2

%A _David W. Wilson_

%E More terms from _Robert G. Wilson v_, Feb 18 2004

%E a(25)-a(29) from _Robert G. Wilson v_, Feb 22 2006

%E First two terms inserted by _Eric M. Schmidt_, Feb 05 2013