Triangle read by rows, iterates of X * [1,0,0,0,...] where X = an infinite bidiagonal matrix with (2,1,2,1,2,1,...) in the main diagonal, (1,2,1,2,1,2,...) in the subdiagonal and the rest zeros.

A140169

Triangle read by rows, iterates of X * [1,0,0,0,...] where X = an infinite bidiagonal matrix with (2,1,2,1,2,1,...) in the main diagonal, (1,2,1,2,1,2,...) in the subdiagonal and the rest zeros.