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 A231712 #50 Sep 08 2022 08:46:06
%S A231712 0,1,5,29,259,3129,46661,823549,16777223,387420497,10000000009,
%T A231712 285311670621,8916100448267,302875106592265,11112006825558029,
%U A231712 437893890380859389,18446744073709551631,827240261886336764193,39346408075296537575441,1978419655660313589123997
%N A231712 a(n) = n^n + n - 1.
%C A231712 Supersequence of A187605 (primes of the form n^n + n - 1).
%C A231712 Numbers n such that a(n) = prime: 2, 3, 19, 30, 535, 1551, ..., another term > 2300 (see A058912 and A187605).
%C A231712 Also generalization of the problem: "What is the minimum length of a text consisting only of the first n letters of the alphabet and containing all possible n-tuples (no blanks)?" (see Puzzleup link). Example for n = 3, length of text a(3) = 29: AAABAACABBABCACBACCBBBCBCCCAA, all triples (AAA, AAB, ..., CCC) occurring exactly once. - _Jörg Zurkirchen_, Sep 06 2014
%H A231712 Jaroslav Krizek, <a href="/A231712/b231712.txt">Table of n, a(n) for n = 0..50</a>
%H A231712 PuzzleUp, <a href="/A231712/a231712_1.png">Problem No. 04: Four Letters, August 20, 2014</a>.
%F A231712 a(n) = A066279(n) - 2 = A066068(n) - 1.
%F A231712 E.g.f.: 1/(1 + LambertW(-x)) + (x-1)*exp(x). - _Alois P. Heinz_, Jun 15 2018
%p A231712 A231712:=n->n^n+n-1: seq(A231712(n), n=0..20); # _Wesley Ivan Hurt_, Sep 23 2014
%t A231712 Join[{0}, Table[n^n + n - 1, {n, 18}]]
%o A231712 (PARI) a(n)=n^n+n-1 \\ _Edward Jiang_, Sep 06 2014
%o A231712 (Magma) [n^n+n-1 : n in [0..20]]; // _Wesley Ivan Hurt_, Sep 23 2014
%Y A231712 Cf. A187605, A058912, A066279, A066068.
%K A231712 nonn
%O A231712 0,3
%A A231712 _Jaroslav Krizek_, Nov 12 2013