Repeat a vector with increment

Given

vector a = (1:N)'; with N consecutive integers
how to generate
matrix b = [a a+1 a+2 ... a+M]; with M columns, each column incremented by one.

For example

N = 3; M = 3;
a = (1:3)';
b = [(1:3)'  (2:4)'  (3:5)'  (4:6)'];

Answer 1

[Star Strider]

This works:

N = 3; 
M = 3;
a = (1:3)';
b = bsxfun(@plus, a, [0:M-1])

b =
     1     2     3
     2     3     4
     3     4     5