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 A151894 #20 Jun 10 2025 01:13:53
%S A151894 2,3,5,6,7,8,11,17,42,66,76,93,139,157,226,290,415,522,774,794,1947
%N A151894 Numbers k such that k! + second prime after k! is prime.
%C A151894 Because numbers of the form (k! + prime) are divisible by all primes <= k that means that the first prime number can have the form k! + next prime after k! and no primes of the form k! + m for m > 1 and m < next prime after k!.
%t A151894 a = {}; Do[If[PrimeQ[n! + NextPrime[n!,2]], AppendTo[a, n]], {n, 200}]; a
%o A151894 (PARI) is(k) = {my(f = k!); isprime(f + nextprime(nextprime(f + 1) + 1));} \\ _Amiram Eldar_, Oct 23 2024
%Y A151894 Cf. A002981, A151892, A151893, A151903.
%K A151894 nonn,more,hard
%O A151894 1,1
%A A151894 _Artur Jasinski_, Apr 12 2008
%E A151894 a(15)-a(20) from _Amiram Eldar_, Oct 23 2024
%E A151894 a(21) from _Michael S. Branicky_, Oct 24 2024