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%I M5461 #37 Nov 06 2023 07:17:14
%S 561,1105,1729,1905,2047,2465,4033,4681,6601,8321,8481,10585,12801,
%T 15841,16705,18705,25761,30121,33153,34945,41041,42799,46657,52633,
%U 62745,65281,74665,75361,85489,87249,90751,113201,115921,126217,129921,130561,149281,158369
%N Composite numbers k such that k == +-1 (mod 8) and 2^((k-1)/2) == 1 (mod k).
%C Previous name was "Terms of A047713 that are congruent to +-1 mod 8".
%C Complement of (A244626 union A244628) with respect to A047713. - _Jianing Song_, Sep 18 2018
%D Richard K. Guy, Unsolved Problems in Number Theory, 3rd Edition, Springer, 2004, Section A12, pp. 44-50.
%D Hans Riesel, Prime numbers and computer methods for factorization, Progress in Mathematics, Vol. 57, Birkhäuser, Boston, 1985.
%D N. J. A. Sloane and Simon Plouffe, The Encyclopedia of Integer Sequences, Academic Press, 1995 (includes this sequence).
%H Amiram Eldar, <a href="/A006971/b006971.txt">Table of n, a(n) for n = 1..10000</a> (terms 1..828 from Jianing Song using data from A047713)
%t Select[Range[10^5], MemberQ[{1, 7}, Mod[#, 8]] && CompositeQ[#] && PowerMod[2, (# - 1)/2, #] == 1 &] (* _Amiram Eldar_, Nov 06 2023 *)
%Y Subsequence of A001567 and A047713.
%Y Cf. A244626, A244628, A270697, A270698.
%K nonn
%O 1,1
%A _Richard Pinch_
%E This sequence appeared as M5461 in Sloane-Plouffe (1995), but was later mistakenly declared to be an erroneous form of A047713. Thanks to _Jianing Song_ for providing the correct definition. - _N. J. A. Sloane_, Sep 17 2018
%E Formal definition by _Jianing Song_, Sep 18 2018