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A208156 8-Knödel numbers.

%I A208156 #24 Feb 16 2025 08:33:16
%S A208156 12,14,16,20,24,32,40,48,56,60,80,88,96,104,120,136,140,152,160,184,
%T A208156 224,232,240,248,260,296,308,328,344,376,408,416,424,472,480,488,528,
%U A208156 536,560,568,584,632,664,680,712,728,776,808,824,856,872,904,1016,1040
%N A208156 8-Knödel numbers.
%H A208156 Amiram Eldar, <a href="/A208156/b208156.txt">Table of n, a(n) for n = 1..10000</a>
%H A208156 Eric Weisstein's World of Mathematics, <a href="https://mathworld.wolfram.com/KnoedelNumbers.html">Knödel Numbers</a>
%p A208156 with(numtheory);
%p A208156 knodel:=proc(i,k)
%p A208156 local a,n,ok;
%p A208156 for n from k+1 to i do
%p A208156   ok:=1;
%p A208156   for a from 1 to n do
%p A208156      if gcd(a,n)=1 then  if (a^(n-k) mod n)<>1 then ok:=0; break; fi; fi;
%p A208156   od;
%p A208156   if ok=1 then print(n); fi;
%p A208156 od;
%p A208156 end:
%p A208156 knodel(10000,8)
%t A208156 Select[Range[10, 2000, 2], Divisible[# - 8, CarmichaelLambda[#]]&] (* _Jean-François Alcover_, Mar 01 2018 *)
%Y A208156 Cf. A002997, A050990, A033553, A050992, A050993, A208154, A208155, A208157, A208158.
%K A208156 nonn
%O A208156 1,1
%A A208156 _Paolo P. Lava_, Feb 24 2012