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 A188776 #39 Jun 20 2022 04:18:13
%S A188776 1,2,9,30,6871,185779,208541,813162,864355,2573155
%N A188776 Numbers n such that Sum_{k=1..n} k^k == 1 (mod n).
%C A188776 Numbers n such that A001923(n) == 1 (mod n).
%C A188776 a(11) > 10^7. - _Hiroaki Yamanouchi_, Aug 25 2015
%t A188776 Union@Table[If[Mod[Sum[PowerMod[i,i,n],{i,1,n}],n]==1,Print[n];n],{n,1,20000}]
%o A188776 (PARI)
%o A188776 f(n)=lift(sum(k=1, n, Mod(k, n)^k));
%o A188776 for(n=1, 10^6, if(f(n)==1, print1(n, ", "))) /* _Joerg Arndt_, Apr 10 2011 */
%o A188776 (Python)
%o A188776 from itertools import accumulate, count, islice
%o A188776 def A188776_gen(): # generator of terms
%o A188776 yield 1
%o A188776 for i, j in enumerate(accumulate(k**k for k in count(2)),start=2):
%o A188776 if not j % i:
%o A188776 yield i
%o A188776 A188776_list = list(islice(A188776_gen(),5)) # _Chai Wah Wu_, Jun 18 2022
%Y A188776 Cf. A001923, A128981 (sum == 0 mod n), A188775 (sum == -1 mod n).
%K A188776 nonn,more
%O A188776 1,2
%A A188776 _José María Grau Ribas_, Apr 10 2011
%E A188776 a(6)-a(9) from _Lars Blomberg_, May 10 2011
%E A188776 a(1) inserted and a(10) added by _Hiroaki Yamanouchi_, Aug 25 2015