This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.
%I A051856 #35 Jan 30 2025 14:43:25
%S A051856 0,1,2,3,4,6,76,2837,6001,7076
%N A051856 Numbers k such that (k!)^2 + k! + 1 is prime.
%D A051856 H. Dubner, Factorial and primorial primes, J. Rec. Math., 19 (No. 3) (1987)
%H A051856 C. K. Caldwell, <a href="http://www.utm.edu/research/primes/">The Prime Pages</a>
%H A051856 C. Nash, <a href="http://pages.prodigy.net/chris_nash/primeform.html">Prime Form</a> [broken link]
%H A051856 M. Oakes, <a href="http://groups.yahoo.com/group/primeform/message/10881">Re: Gaussian primorial and factorial primes</a>, Primeform, Dec 21 2010 [broken link]
%H A051856 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 A051856 6 is in the sequence because (6!)^2+6!+1=519121 is prime.
%t A051856 Do[If[PrimeQ[n!^2+n!+1], Print[n]], {n, 600}] (* _Farideh Firoozbakht_, Jul 12 2003 *)
%Y A051856 Cf. A002981, A002982, A046029.
%K A051856 nonn,hard,more
%O A051856 1,3
%A A051856 Andrew Walker (ajw01(AT)uow.edu.au), Dec 13 1999
%E A051856 Edited by _R. J. Mathar_, Aug 08 2008
%E A051856 a(8)-a(10) from _Serge Batalov_, Nov 24 2011