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A081759 Numbers n such that 5n+6 is prime. 14

%I #27 Feb 04 2024 01:15:09

%S 1,5,7,11,13,19,25,29,35,37,41,47,49,53,55,61,65,79,83,85,91,97,103,

%T 107,113,119,125,127,131,137,139,149,151,161,163,175,181,187,193,197,

%U 203,205,209,211,217,229,233,235,239,245,257,259,263,271,275,289

%N Numbers n such that 5n+6 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

%H Nathaniel Johnston, <a href="/A081759/b081759.txt">Table of n, a(n) for n = 1..10000</a>

%F a(n) = 2*A024912(n) - 1.

%p A081759 := proc(n) option remember: local k: if(n=1)then return 1: fi: for k from procname(n-1)+1 do if(isprime(5*k+6))then return k: fi: od: end: seq(A081759(n),n=1..100); # _Nathaniel Johnston_, May 28 2011

%t Select[Range[300], PrimeQ[5# + 6] &] (* _Ray Chandler_, Dec 06 2006 *)

%o (Magma) [n: n in [0..300]| IsPrime(5*n + 6)]; // _Vincenzo Librandi_, Oct 16 2012

%o (PARI) is(n)=isprime(5*n+6) \\ _Charles R Greathouse IV_, Feb 17 2017

%Y Cf. A024912, A030430, A049511, A067076, A087505, A089192, A089253.

%K easy,nonn

%O 1,2

%A _Giovanni Teofilatto_, Nov 21 2003

%E Corrected by _Ray Chandler_, Nov 22 2003

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Last modified March 29 03:51 EDT 2024. Contains 371264 sequences. (Running on oeis4.)