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A124731 Triangle, row sums = powers of 3, companion to A124730.

%I A124731 #6 Mar 03 2013 13:48:18
%S A124731 1,2,1,4,3,2,8,7,10,2,16,15,34,12,4,32,31,98,46,32,4,64,63,258,144,
%T A124731 156,36,8,128,127,642,402,600,192,88,8,256,255,1538,1044,2004,792,560,
%U A124731 96,16
%N A124731 Triangle, row sums = powers of 3, companion to A124730.
%C A124731 In A124730, the diagonals are switched. Row sums are powers of 3 in both triangles.
%F A124731 Let M = the infinite bidiagonal matrix with (2,1,2,1...) in the main diagonal and (1,2,1,2...) in the subdiagonal. Extracting finite n X n matrices of this form, we take M^n * [1,0,0,0...].
%e A124731 Row 2 = (4, 3, 2) since (using the 3 X 3 matrix m = [2,0,0; 1,1,0; 0,2,2]), m^2 * [1,0,0] = [4,3,2].
%e A124731 First few rows of the triangle are:
%e A124731 1;
%e A124731 2, 1;
%e A124731 4, 3, 2;
%e A124731 8, 7, 10, 2;
%e A124731 16, 15, 34, 12, 4;
%e A124731 32, 31, 98, 46, 32, 4;
%e A124731 64, 63, 258, 144, 156, 36, 8;
%e A124731 ...
%Y A124731 Cf. A124730, A124732.
%K A124731 nonn,tabl
%O A124731 0,2
%A A124731 _Gary W. Adamson_ & _Roger L. Bagula_, Nov 05 2006