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Even numbers k such that k/2 - 1 is prime.
6

%I #19 Sep 08 2022 08:45:12

%S 6,8,12,16,24,28,36,40,48,60,64,76,84,88,96,108,120,124,136,144,148,

%T 160,168,180,196,204,208,216,220,228,256,264,276,280,300,304,316,328,

%U 336,348,360,364,384,388,396,400,424,448,456,460,468,480,484

%N Even numbers k such that k/2 - 1 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 Vincenzo Librandi, <a href="/A089241/b089241.txt">Table of n, a(n) for n = 1..5000</a>

%F a(n) = 2*prime(n) + 2. - _Alonso del Arte_, Mar 02 2017

%t 2Prime[Range[100]] + 2 (* _Alonso del Arte_, Mar 06 2017 *)

%o (PARI) a(n)=2*prime(n) + 2 \\ _Charles R Greathouse IV_, Mar 06 2017

%o (Magma) [2*NthPrime(n)+2: n in [1..60]]; // _Vincenzo Librandi_, Jan 09 2018

%Y a(n) = A072055(n) + 1.

%Y a(n) = A029933(A000040(n)).

%K easy,nonn

%O 1,1

%A _Giovanni Teofilatto_, Dec 22 2003

%E Corrected (62 replaced by 64, 202 replaced by 204, 314 by 316, 386 by 388) by _R. J. Mathar_, Apr 22 2010

%E Offset corrected by _Arkadiusz Wesolowski_, Aug 09 2011