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 A288491 #27 Jan 05 2025 23:39:48 %S A288491 2,6,40,56,954 %N A288491 Numbers k such that k^k*prime(k) - 1 is prime. %C A288491 a(6) > 22000. - _Giovanni Resta_, Jun 12 2017 %C A288491 a(6) > 40000. - _Michael S. Branicky_, Jan 05 2025 %e A288491 a(1) = 2 because 3*2^2-1 = 11 a prime. %e A288491 a(2) = 6 because 13*6^6-1 = 606527 a prime. %t A288491 Select[Range[1000], PrimeQ[Prime[#] #^# - 1] &] %o A288491 (Magma) [n: n in [1..1000] | IsPrime(NthPrime(n)*n^n-1)]; %Y A288491 Cf. A086173. %K A288491 nonn,more %O A288491 1,1 %A A288491 _Vincenzo Librandi_, Jun 10 2017