A097480 - OEIS

%I #26 Feb 04 2024 01:17:49

%S 9,10,11,13,14,16,17,19,22,23,26,28,29,31,34,37,38,41,43,44,47,49,52,

%T 56,58,59,61,62,64,71,73,76,77,82,83,86,89,91,94,97,98,103,104,106,

%U 107,113,119,121,122,124,127,128,133,136,139,142,143,146,148,149,154,161,163

%N Positive integers n such that 2n-15 is prime.

%H Shawn A. Broyles, <a href="/A097480/b097480.txt">Table of n, a(n) for n = 1..1000</a>

%F Half of p+15 where p is a prime greater than 2.

%t (Prime[Range[2,100]]+15)/2 (* _Vladimir Joseph Stephan Orlovsky_, Feb 08 2010 *)

%t Select[Range[9,200],PrimeQ[2#-15]&] (* _Harvey P. Dale_, Apr 04 2021 *)

%o (PARI) is(n)=isprime(2*n-15) \\ _Charles R Greathouse IV_, Jul 12 2016

%Y Cf. A000040, A098602, A098603.

%Y Numbers n such that 2n+k is prime: A005097 (k=1), A067076 (k=3), A089038 (k=5), A105760 (k=7), A155722 (k=9), A101448 (k=11), A153081 (k=13), A089559 (k=15), A173059 (k=17), A153143 (k=19).

%Y Numbers n such that 2n-k is prime: A006254 (k=1), A098090 (k=3), A089253 (k=5), A089192 (k=7), A097069 (k=9), A097338 (k=11), A097363 (k=13), this sequence (k=15), A098605 (k=17), A097932 (k=19).

%K easy,nonn

%O 1,1

%A Douglas Winston (douglas.winston(AT)srupc.com), Sep 19 2004