A178835 - OEIS

%I #9 Sep 08 2022 08:45:54

%S 37,151,607,39845887,41781441855487,10696049115004927,

%T 11760430373211112611541680127,

%U 206891679087930585785731761318515072565247,52964269846510229961147330897539858576703487,888592995497188974267840378291500075950806986129407

%N Primes of the form 19 * 2^n - 1.

%C Main entry for this sequence is A001775.

%C Also primes of the form 38 * 4^n - 1, since even-numbered exponents yield numbers divisible by three.

%H Vincenzo Librandi, <a href="/A178835/b178835.txt">Table of n, a(n) for n = 1..20</a>

%t Select[19*2^Range[140]-1,PrimeQ] (* _Harvey P. Dale_, Mar 07 2014 *)

%o (Magma) [a: n in [0..250] | IsPrime(a) where a is (19 * 2^n - 1)]; // _Vincenzo Librandi_, Mar 08 2014

%K nonn

%O 1,1

%A Kevin Batista (kevin762401(AT)yahoo.com), Jun 16 2010

%E Edited by _Charles R Greathouse IV_, Aug 29 2010

%E Edited by _Charles R Greathouse IV_, Sep 02 2010

%E More terms from _Harvey P. Dale_, Mar 07 2014