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%I #11 Oct 31 2016 13:48:45
%S 3,7,11,13,19,29,37,43,53,61,71,89,103,131,151,173,181,223,229,239,
%T 251,281,311,349,359,409,433,503,541,571,593,601,619,659,661,683,691,
%U 701,719,769,827,857,911,941,953,997,1069,1087,1091,1129,1163,1223,1291
%N Primes p such that p^k == 1 modulo k, where p=prime(k).
%C A077254(A049084(a(n))) = 1; a(n) = A000040(A077255(n)).
%H Robert Israel, <a href="/A077256/b077256.txt">Table of n, a(n) for n = 1..10000</a>
%p g:= proc(t) local p; p:= ithprime(t); if p&^ t mod t = 1 then p else NULL fi end proc:
%p map(g, [$1..1000]); # _Robert Israel_, Oct 31 2016
%t With[{no=250}, Transpose[Select[Partition[Riffle[Prime[Range[no]], Range[no]],2], PowerMod[First[#],Last[#],Last[#]]==1&]][[1]]] (* _Harvey P. Dale_, Jan 05 2011 *)
%t Prime[Select[Range[250]], PowerMod[Prime[#],#,#]==1&]]
%Y Cf. A000040, A049084, A077254, A077255.
%Y Contains A048891.
%K nonn
%O 1,1
%A _Reinhard Zumkeller_, Oct 31 2002