The OEIS Foundation is supported by donations from users of the OEIS and by a grant from the Simons Foundation.



Thanks to everyone who made a donation during our annual appeal!
To see the list of donors, or make a donation, see the OEIS Foundation home page.

(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A051856 Numbers n such that (n!)^2+n!+1 is prime. 6


%S 0,1,2,3,4,6,76,2837,6001,7076

%N Numbers n such that (n!)^2+n!+1 is prime.

%D H. Dubner, Factorial and primorial primes, J. Rec. Math., 19 (No. 3) (1987)

%H C. K. Caldwell, <a href="http://www.utm.edu/research/primes/">The Prime Pages</a>

%H C. Nash, <a href="http://pages.prodigy.net/chris_nash/primeform.html">Prime Form</a> [broken link]

%H M. Oakes, <a href="http://groups.yahoo.com/group/primeform/message/10881">Re: Gaussian primorial and factorial primes</a>, Primeform, Dec 21 2010

%H Mike Oakes, Andrew Walker, David Broadhurst, <a href="/A046029/a046029.txt">Gaussian primorial and factorial primes</a>, digest of 7 messages in primeform Yahoo group, Dec 20 - Dec 21, 2010.

%e 6 is in the sequence because (6!)^2+6!+1=519121 is prime.

%t Do[If[PrimeQ[n!^2+n!+1], Print[n]], {n, 600}] (* _Farideh Firoozbakht_, Jul 12 2003 *)

%Y Cf. A002981, A002982, A046029.

%K nonn,hard,more

%O 1,3

%A Andrew Walker (ajw01(AT)uow.edu.au), Dec 13 1999

%E Edited by _R. J. Mathar_, Aug 08 2008

%E a(8)-a(10) from _Serge Batalov_, Nov 24 2011

Lookup | Welcome | Wiki | Register | Music | Plot 2 | Demos | Index | Browse | More | WebCam
Contribute new seq. or comment | Format | Style Sheet | Transforms | Superseeker | Recent
The OEIS Community | Maintained by The OEIS Foundation Inc.

License Agreements, Terms of Use, Privacy Policy. .

Last modified January 20 08:07 EST 2020. Contains 331081 sequences. (Running on oeis4.)