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A256347 Moduli n for which A248218(n) = 7.

%I A256347 #7 Mar 10 2021 01:19:29
%S A256347 41,123,131,287,317,393,503,547,727,779,861,917,951,1091,1237,1271,
%T A256347 1277,1509,1517,1627,1637,1641,1681,1763,2089,2181,2219,2239,2337,
%U A256347 2357,2383,2489,2531,2671,2751,2789
%N A256347 Moduli n for which A248218(n) = 7.
%C A256347 If x is a member, and y is a member of this sequence or A248219, then LCM(x,y) is a member. - _Robert Israel_, Mar 09 2021
%H A256347 Robert Israel, <a href="/A256347/b256347.txt">Table of n, a(n) for n = 1..4000</a>
%p A256347 filter:= proc(n) local x, k, R,p;
%p A256347   x:= 0; R[0]:= 0;
%p A256347   for k from 1 do
%p A256347     x:= x^2+1 mod n;
%p A256347     if assigned(R[x]) then return evalb(k-R[x] = 7)
%p A256347     else R[x]:= k
%p A256347     fi
%p A256347   od;
%p A256347 end proc:
%p A256347 select(filter, [$1..10000]); # _Robert Israel_, Mar 09 2021
%o A256347 (PARI) for(i=1,3000,A248218(i)==7&&print1(i","))
%Y A256347 Cf. A248218, A248219, A256342 - A256349, A003095, A247981.
%K A256347 nonn
%O A256347 1,1
%A A256347 _M. F. Hasler_, Mar 25 2015