Pascal matrix.

  PASCAL(N) is the Pascal matrix of order N: a symmetric positive

  definite matrix with integer entries, made up from Pascal's

  triangle.  Its inverse has integer entries.

  PASCAL(N,1) is the lower triangular Cholesky factor (up to signs

  of columns) of the Pascal matrix.  It is involutary (is its own


  PASCAL(N,2) is a transposed and permuted version of PASCAL(N,1)

  which is a cube root of the identity.