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Primes of the form n!!! + 1.
59

%I #16 Jul 10 2014 03:23:56

%S 2,3,5,11,19,29,163,281,881,209441,264539521,72642169601,

%T 9927882482918401,26582634158080001,141383412854531380076544001,

%U 427380210218181008588800001,2295148179742698933452800001

%N Primes of the form n!!! + 1.

%H Vincenzo Librandi, <a href="/A037082/b037082.txt">Table of n, a(n) for n = 1..26</a>

%H <a href="/index/Fa#factorial">Index entries for sequences related to factorial numbers</a>

%e 11!!! + 1 = 11*8*5*2 + 1 = 881 is prime.

%t Select[Table[Times@@Range[n,1,-3]+1,{n,60}],PrimeQ] (* _Harvey P. Dale_, Jul 09 2014 *)

%Y Cf. A007661, A037083.

%K nonn

%O 1,1

%A _G. L. Honaker, Jr._