Here is a solution in one line :
A = [1 2 3];
B = [2 3 4 1; 1 2 3 4; 2 4 1 3; 2 3 1 4];
% Reshape B in a 1D array (all rows in a line)
C = reshape(B', [1, numel(B)]);
% Then use strfind to find a pattern in a string pattern within a string
linear_index = strfind(C, A);
% Compute the row number of the pattern knowing the initial number of columns
row_number = ceil(linear_index/size(B, 2));
% Or do it in a single line :
row_number = ceil(strfind(reshape(B', [1, numel(B)]), A)/size(B, 2));
