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%I #36 Mar 16 2024 11:20:27
%S 1,2,1,2,8,3,6,4,7,8,14,5,27,6,10,11,19,7,12,8,13,14,33,9,35,27,16,23,
%T 40,10,18,11,32,19,34,20,21,12,51,22,38,13,55,14,24,33,60,15,25,35,26,
%U 27,47,16,29,39,30,40,71,17,93,18,54,31,77,32,79,19,33,34,61,20,172,21,35,36
%N The smallest k such that prime(k) == -1 (mod n).
%C Numbers n such that a(n) + 1 = a(n + 1) where the a(n)-th prime is not the smaller prime in a twin prime pair: 1, 3, 122, 267, 356, 362, 392, 403, 416, 446, 514, ....
%C Primes p(n) such that p is not -1 mod n for all prime p < p(n): 2, 3, 11, 31, 41, 59, 83, 97, 101, 109, 167, 191, 211, 277, 283, 313, 331, 367, 419,... Also primes p(n) such that p(n) <= A038700(n).
%H Paolo P. Lava, <a href="/A219109/b219109.txt">Table of n, a(n) for n = 1..1000</a>
%F a(n) = A000720(A038700(n)). - _Joerg Arndt_, Apr 16 2013
%e For n = 11, we see that the 14th prime (43), modulo 11 is 10, or -1, so a(11) = 14.
%o (PARI) a(n)=forstep(t=n-1,n^99,n,if(isprime(t),return(primepi(t)))) \\ _Charles R Greathouse IV_, Mar 17 2014
%Y Cf. A038700, A221861.
%K nonn
%O 1,2
%A _Irina Gerasimova_, Apr 11 2013
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