A208156 - OEIS

%I #24 Feb 16 2025 08:33:16

%S 12,14,16,20,24,32,40,48,56,60,80,88,96,104,120,136,140,152,160,184,

%T 224,232,240,248,260,296,308,328,344,376,408,416,424,472,480,488,528,

%U 536,560,568,584,632,664,680,712,728,776,808,824,856,872,904,1016,1040

%N 8-Knödel numbers.

%H Amiram Eldar, <a href="/A208156/b208156.txt">Table of n, a(n) for n = 1..10000</a>

%H Eric Weisstein's World of Mathematics, <a href="https://mathworld.wolfram.com/KnoedelNumbers.html">Knödel Numbers</a>

%p with(numtheory);

%p knodel:=proc(i,k)

%p local a,n,ok;

%p for n from k+1 to i do

%p   ok:=1;

%p   for a from 1 to n do

%p      if gcd(a,n)=1 then  if (a^(n-k) mod n)<>1 then ok:=0; break; fi; fi;

%p   od;

%p   if ok=1 then print(n); fi;

%p od;

%p end:

%p knodel(10000,8)

%t Select[Range[10, 2000, 2], Divisible[# - 8, CarmichaelLambda[#]]&] (* _Jean-François Alcover_, Mar 01 2018 *)

%Y Cf. A002997, A050990, A033553, A050992, A050993, A208154, A208155, A208157, A208158.

%K nonn,changed

%O 1,1

%A _Paolo P. Lava_, Feb 24 2012