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%I #5 Mar 30 2012 18:38:57
%S 1,1,1,1,4,1,64,4,65536,512,33554432,65536,68719476736,6442450944,
%T 9007199254740992,281474976710656,220326730624766167090200576,
%U 340010386766614455386112,486777830487640090174734030864384
%N Let M_n be the n X n matrix M_(i,j)=1/(i+j+ij); a(n) is the numerator of det(M_n).
%C Is a(n) always of the form 2^u*3^v?
%o (PARI) for(n=1,70,print1(numerator(matdet(matrix(n,n,i,j,1/(i*j+i+j)))),","))
%K easy,nonn
%O 1,5
%A _Benoit Cloitre_, Apr 21 2002