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 A142959 #15 Aug 12 2025 17:32:32
%S A142959 1,2,3,4,76
%N A142959 Numbers k such that both (k!)^2 + k! + 1 and (k!)^2 + 1 are prime.
%C A142959 For the numbers of digits of the associated primes, see A142960.
%C A142959 a(6) > 150000, because A46029(15) > 150000 and A46029(14) = 127162 is not a term here since (127162!)^2 + 127162! + 1 is divisible by 2049703. - _Giovanni Resta_, Aug 12 2025
%D A142959 J.-M. De Koninck, Ces nombres qui nous fascinent, Entry 76, pp 26, Ellipses, Paris 2008.
%F A142959 A046029 INTERSECT A051856. - _R. J. Mathar_, Aug 08 2008
%t A142959 Select[Range[80],With[{c=#!},AllTrue[c^2+{c+1,1},PrimeQ]]&] (* _Harvey P. Dale_, Aug 11 2025 *)
%Y A142959 Cf. A142960, A046029, A051856.
%K A142959 nonn,more
%O A142959 1,2
%A A142959 _Lekraj Beedassy_, Jul 13 2008