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 A219018 #17 Feb 07 2023 12:43:38
%S A219018 1,3,5,43,17,47,51,1697,59,512,521,3255,8189,18951,656
%N A219018 Smallest number k > 0 such that k^n + 1 has exactly n distinct prime factors.
%C A219018 a(16) > 2 * 10^6; a(18) = 19208. - _Daniel Suteu_, Feb 06 2023
%e A219018 a(3) = 5 is the smallest number of the set {k(i)} = {5, 9, 10, 11, 12, 13, 14, 19,….} where k(i)^3 + 1 has exactly 3 distinct prime factors.
%p A219018 with(numtheory) :for n from 1 to 10 do:ii:=0:for k from 1 to 10^10 while(ii=0) do:x:=k^n+1:y:=factorset(x):n1:=nops(y):if n1=n then ii:=1: printf ( "%d %d \n",n,k):
%p A219018 else fi:od:od:
%t A219018 L = {}; Do[n = 1; While[Length[FactorInteger[n^k + 1]] != k, n++]; Print@AppendTo[L, n], {k, 15}] (* _Giovanni Resta_, Nov 09 2012 *)
%o A219018 (PARI) a(n) = my(k=1); while (omega(k^n+1) != n, k++); k; \\ _Daniel Suteu_, Feb 06 2023
%Y A219018 Cf. A180278, A001221, A281940.
%K A219018 nonn,more,hard
%O A219018 1,2
%A A219018 _Michel Lagneau_, Nov 09 2012
%E A219018 Definition clarified by _Daniel Suteu_, Feb 06 2023
%E A219018 a(13)-a(15) from _Daniel Suteu_, Feb 06 2023