
EXAMPLE

Illustrate the coefficients in (1+x+x^2x^3)^n by:
n=0: [1];
n=1: [1, 1, 1, 1];
n=2: [1, 2, 3, 0, 1, 2, 1];
n=3: [1, 3, 6, 4, 0, 6, 2, 0, 3, 1];
n=4: [1, 4, 10, 12, 7, 8, 12, 8, 7, 4, 2, 4, 1];
n=5: [1, 5, 15, 25, 25, 1, 25, 35, 5, 15, 21, 5, 5, 5, 5, 1];
n=6: [1, 6, 21, 44, 60, 36, 24, 84, 66, 0, 66, 36, 4, 36, 0, 4, 9, 6, 1];
n=7: [1, 7, 28, 70, 119, 119, 28, 132, 210, 126, 84, 168, 98, 70, 76, 28, 49, 7, 0, 14, 7, 1]; ...
This sequence gives the sums of the absolute values of the coefficients for n>=0.
