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%I #19 Feb 04 2024 01:16:58
%S -1,0,1,3,4,6,9,10,13,15,16,18,19,24,25,30,31,33,36,39,40,43,46,48,51,
%T 54,55,58,61,64,66,69,75,76,81,85,88,90,93,94,103,106,108,109,114,115,
%U 118,120,121,123,124,129,135,139,141,145,148,150,153,156,159,160,163,169
%N Numbers n such that 4n + 7 is prime.
%D M. Cerasoli, F. Eugeni and M. Protasi, Elementi di Matematica Discreta, Bologna 1988.
%D Emanuele Munarini and Norma Zagaglia Salvi, Matematica Discreta,UTET, CittaStudiEdizioni, Milano 1997.
%F a(n) = A005099(n) - 2 = A095278(n) - 1.
%p A089986:=n->`if`(isprime(4*n+7), n, NULL): seq(A089986(n), n=-1..200); # _Wesley Ivan Hurt_, Sep 18 2014
%t Select[Range[-1, 200], PrimeQ[4 # + 7] &] (* _Wesley Ivan Hurt_, Sep 18 2014 *)
%o (Magma) [ n: n in [-1..170] | IsPrime(4*n+7) ];
%o (PARI) is(n)=isprime(4*n+7) \\ _Charles R Greathouse IV_, Feb 20 2017
%Y Cf. A005099 ((( Primes = -1 mod 4 ) + 1)/4), A005098 (4n+1 is prime), A095278 (4n+3 is prime), A111215 (4n+5 is prime).
%K sign
%O 1,4
%A _Giovanni Teofilatto_, Jan 13 2004
%E Edited and extended by _Klaus Brockhaus_, Dec 22 2008
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