%I A003560
%S A003560 1,3,3,2,3,5,7,5,9,5,6,21,13,9,15,3,11,9,15,27,4,11,5,12,
%T A003560 25,6,9,7,6,55,25,7,9,17,23,7,37,12,13,33,10,39,43,29,45,
%U A003560 9,9,24,49,33,5,45,35,15,12,30,19,29,39,6
%N A003560 Least number m such that 4^m = +- 1 mod 4n + 1.
%Y A003560 Sequence in context: A031352 A057853 A129309 this_sequence A123676 A122775 
               A086632
%Y A003560 Adjacent sequences: A003557 A003558 A003559 this_sequence A003561 A003562 
               A003563
%K A003560 nonn
%O A003560 0,2
%A A003560 N. J. A. Sloane (njas(AT)research.att.com).