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 A056788 #26 Mar 07 2025 11:39:56
%S A056788 2,5,31,283,3381,49781,870199,17600759,404197705,10387420489,
%T A056788 295311670611,9201412118867,311791207040509,11414881932150269,
%U A056788 449005897206417391,18884637964090410991,845687005960046315793,40173648337182874339601,2017766063735610126699403
%N A056788 a(n) = n^n + (n-1)^(n-1).
%C A056788 For even n > 1, the absolute value of the discriminant of the polynomial x^n+x-1. [Corrected by _Artur Jasinski_, May 07 2010]
%C A056788 The largest known prime in this sequence is a(4) = 283.
%D A056788 R. P. Stanley, Enumerative Combinatorics, Cambridge, Vol. 2, 1999; see equation (6.7).
%H A056788 Pierre Letouzey, <a href="https://arxiv.org/abs/2502.12615">Generalized Hofstadter functions G, H and beyond: numeration systems and discrepancy</a>, arXiv:2502.12615 [cs.DM], 2025. See p. 18.
%H A056788 Walter Nissen, <a href="http://upforthecount.com/math/nnpomega.html">post on np ( n ) = n^n + (n+1)^(n+1)</a>, on home page <a href="http://upforthecount.com">"Up for the count!"</a>. (Updated Oct 02 2012)
%e A056788 a(3) = 2^2 + 3^3 = 4 + 27 = 31.
%t A056788 Join[{2}, Table[n^n+(n-1)^(n-1), {n, 2, 20}]] (* _T. D. Noe_, Aug 13 2004 *)
%t A056788 Join[{2},Total/@Partition[Table[n^n,{n,20}],2,1]] (* _Harvey P. Dale_, Jun 26 2017 *)
%o A056788 (PARI) A056788(n)=n^n+(n-1)^(n-1) \\ _M. F. Hasler_, Oct 02 2012
%Y A056788 Cf. A000312 (n^n), A086797 (discriminant of the polynomial x^n-x-1).
%Y A056788 Cf. A056187, A056790, A192397 (smallest & largest prime factor of a(n), records of the latter), A217435 = bigomega(a(n)).
%K A056788 nonn
%O A056788 1,1
%A A056788 _Walter Nissen_, Aug 20 2000
%E A056788 Minor corrections by _M. F. Hasler_, Oct 02 2012