%I #5 Mar 31 2012 13:21:10
%S 0,0,0,0,0,0,3,0,0,0,7,0,5,6,0,0,0,0,15,0,13,14,19,0,9,10,15,12,21,0,
%T 27,0,0,0,31,0,29,30,35,0,25,26,27,28,0,38,27,0,17,18,0,20,45,30,51,
%U 24,25,42,55,0,45,54,59,0,0,0,63,0,61,62,67,0,57,58,71,60,69,70,63,0
%N Largest natural number m < n, such that there exists nonzero solutions to a cross-domain congruence m*i = n X i, zero if no such integer exists.
%C Here * stands for ordinary multiplication and X means carryless (GF(2)[X]) multiplication (A048720).
%H <a href="/index/Con#CongruCrossDomain">Index entries for sequences defined by congruent products between domains N and GF(2)[X]</a>
%Y a(2n) = 2*a(n). Bisection A115860 gives the terms at odd positions. Differs from A115869 for the first time at n=23, where a(23)=19, while A115869(23)=15. Cf. A115857, A115861, A115871.
%K nonn
%O 1,7
%A _Antti Karttunen_, Feb 07 2006