Alternating ones and twos tridiagonal matrices ( columns of 1's and twos) to give a triangular sequence: m(n,m,d)=If[ n == m, 1 + (1 - (-1)^(n + 1))/2, If[n == m - 1 || n == m + 1, 1 + (1 - (-1)^n)/2, 0]].

A124036

Alternating ones and twos tridiagonal matrices ( columns of 1's and twos) to give a triangular sequence: m(n,m,d)=If[ n == m, 1 + (1 - (-1)^(n + 1))/2, If[n == m - 1 || n == m + 1, 1 + (1 - (-1)^n)/2, 0]].