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 A077255 #16 Dec 16 2021 04:14:19 %S A077255 2,4,5,6,8,10,12,14,16,18,20,24,27,32,36,40,42,48,50,52,54,60,64,70, %T A077255 72,80,84,96,100,105,108,110,114,120,121,124,125,126,128,136,144,148, %U A077255 156,160,162,168,180,181,182,189,192,200,210,216,220,231,234,240,243,246 %N A077255 Numbers k such that prime(k)^k == 1 (mod k). %C A077255 Contains A023143. All terms not in A023143 are in A060679. - _Robert Israel_, Oct 31 2016 %H A077255 Robert Israel, <a href="/A077255/b077255.txt">Table of n, a(n) for n = 1..10000</a> %F A077255 A077254(a(n)) = 1; A077256(n) = A000040(a(n)). %e A077255 prime(16)^16 mod 16 = 53^16 mod 16 = 3876269050118516845397872321 mod 16 = 1, therefore 16 is a term. %p A077255 select(n -> ithprime(n) &^ n mod n = 1, [$1..1000]); # _Robert Israel_, Oct 31 2016 %t A077255 Select[Range[1000], PowerMod[Prime[#], #, #] == 1&] (* _Jean-François Alcover_, Dec 16 2021 *) %o A077255 (PARI) isok(k) = lift(Mod(prime(k), k)^k) == 1; \\ _Michel Marcus_, Dec 16 2021 %Y A077255 Cf. A000040, A023143, A060679, A077254, A077256. %K A077255 nonn %O A077255 1,1 %A A077255 _Reinhard Zumkeller_, Oct 31 2002