293 ways.Using pennies, nickels, dimes, quarters, half-dollars and dollar coins, there are 293 ways to make change for one dollar in US currency.Method 1:
Using pennies, nickels, dimes, quarters, and half-dollars there are 292 ways to make change for one dollar. In general, to make change for h half-dollars using these coins there are (6 + 55*h + 119*h2 + 95*h3 + 25*h4)/6 ways. For example, putting h=1 gives 50 ways of making change for fifty cents, or h=2 gives 292 ways of making change for dollar etc.
[[ The 292 ways computed above, includes fifty-cent pieces but not the dollar coin so, we must add one more in order to agree with the second method shown below. ]]
Method 2:
Take the Taylor expansion of 1 over (1-x)*(1-x5)*(1-x10)*(1-x25)*(1-x50)*(1-x100), and jot down the coefficient of x100. This is the generating function for the ways to partition 100 into subsets of size 1, 5, 10, 25, 50, or 100, so there are 293 ways to make change for one us dollar.
[[ if we use no dollar coins or half dollars (only pennies, nickels, dimes and quarters) the method 2 gives 242 ways to make a dollar. Those 242 ways begin with line 52. ]]
Indisputable Tally of Combinations- 1 dollar coin
- 2 half dollars
- 1 HD 2Q
- 1 HD 1Q 2D IN
- 1 HD 1Q 2D 5P
- 1 HD 1Q 1D 3N
- 1 HD 1Q 1D 2N 5P
- 1 HD 1Q 1D 1N 10P
- 1 HD 1Q 1D 15P
- 1 HD 1Q 5N
- 1 HD 1Q 4N 5P
- 1 HD 1Q 3N 10P
- 1 HD 1Q 2N 15P
- 1 HD 1Q 1N 20P
- 1 HD 1Q 25P
- 1 HD 5D
- 1 HD 4D 2N
- 1 HD 4D 1N 5P
- 1 HD 4D 10P
- 1 HD 3D 4N
- 1 HD 3D 3N 5P
- 1 HD 3D 2N 10P
- 1 HD 3D 1N 15P
- 1 HD 3D 20P
- 1 HD 2D 6N
- 1 HD 2D 5N 5P
- 1 HD 2D 4N 10P
- 1 HD 2D 3N 15P
- 1 HD 2D 2N 20P
- 1 HD 2D 1N 25P
- 1 HD 2D 30P
- 1 HD 1D 8N
- 1 HD 1D 7N 5P
- 1 HD 1D 6N 10P
- 1 HD 1D 5N 15P
- 1 HD 1D 4N 20P
- 1 HD 1D 3N 25 P
- 1 HD 1D 2N 30 P
- 1 HD 1D 1N 35P
- 1 HD 1D 40P
- 1 HD 10N
- 1 HD 9N 5P
- 1 HD 8N 10P
- 1 HD 7N 15P
- 1 HD 6N 20P
- 1 HD 5N 25P
- 1 HD 4N 30P
- 1 HD 3N 35P
- 1 HD 2N 40P
- 1 HD 1N 45P
- 1 HD 50P
- 4Q
- 3Q 2D 1N
- 3Q 2D 5P
- 3Q 1D 3N
- 3Q 1D 2N 5P
- 3Q 1D 1N 10P
- 3Q 1D 15P
- 3Q 5N
- 3Q 4N 5P
- 3Q 3N 10P
- 3Q 2N 15P
- 3Q 1N 20P
- 3Q 25P
- 2Q 5D
- 2Q 4D 2N
- 2Q 4D 1N 5P
- 2Q 4D 10P
- 2Q 3D 4N
- 2Q 3D 3N 5P
- 2Q 3D 2N 10P
- 2Q 3D 1N 15P
- 2Q 3D 20P
- 2Q 2D 6N
- 2Q 2D 5N 5P
- 2Q 2D 4N 10P
- 2Q 2D 3N 15P
- 2Q 2D 2N 20P
- 2Q 2D 1N 25P
- 2Q 2D 30P
- 2Q 1D 8N
- 2Q 1D 7N 5P
- 2Q 1D 6N 10P
- 2Q 1D 5N 15P
- 2Q 1D 4N 20P
- 2Q 1D 3N 25P
- 2Q 1D 2N 30P
- 2Q 1D 1N 35P
- 2Q 1D 40P
- 2Q 50P
- 2Q 10N
- 2Q 9N 5P
- 2Q 8N 10P
- 2Q 7N 15P
- 2Q 6N 20P
- 2Q 5N 25P
- 2Q 4N 30P
- 2Q 3N 35P
- 2Q 2N 40P
- 2Q 1N 45P
- 1Q 7D 1N
- 1Q 7D 5P
- 1Q 6D 3N
- 1Q 6D 2N 5P
- 1Q 6D 1N 10P
- 1Q 6D 15P
- 1Q 5D 5N
- 1Q 5D 4N 5P
- 1Q 5D 3N 10P
- 1Q 5D 2N 15P
- 1Q 5D 1N 20P
- 1Q 5D 25P
- 1Q 4D 7N
- 1Q 4D 6N 5P
- 1Q 4D 5N 15P
- 1Q 4D 4N 20P
- 1Q 4D 3N 25P
- 1Q 4D 2N 30P
- 1Q 4D 1N 35P
- 1Q 4D 40P
- 1Q 3D 9N
- 1Q 3D 8N 5P
- 1Q 3D 7N 10P
- 1Q 3D 6N 15P
- 1Q 3D 5N 20P
- 1Q 3D 4N 25P
- 1Q 3D 3N 30P
- 1Q 3D 2N 35P
- 1Q 3D 1N 40P
- 1Q 3D 45P
- 1Q 2D 11N
- 1Q 2D 10N 5P
- 1Q 2D 9N 10P
- 1Q 2D 8N 15P
- 1Q 2D 7N 20P
- 1Q 2D 6N 25P
- 1Q 2D 5N 30P
- 1Q 2D 4N 35P
- 1Q 2D 3N 40P
- 1Q 2D 2N 45P
- 1Q 2D 1N 50P
- 1Q 2D 55P
- 1Q 1D 13N
- 1Q 1D 12N 5P
- 1Q 1D 11N 10P
- 1Q 1D 10N 15P
- 1Q 1D 9N 20P
- 1Q 1D 8N 25P
- 1Q 1D 7N 30P
- 1Q 1D 6N 35P
- 1Q 1D 5N 40P
- 1Q 1D 4N 45P
- 1Q 1D 3N 50P
- 1Q 1D 2N 55P
- 1Q 1D 1N 60P
- 1Q 1D 65P
- 1Q 15N
- 1Q 14N 5P
- 1Q 13N 10P
- 1Q 12N 15P
- 1Q 11N 20P
- 1Q 10N 25P
- 1Q 9N 30P
- 1Q 8N 35P
- 1Q 7N 40P
- 1Q 6N 45P
- 1Q 5N 50P
- 1Q 4N 55P
- 1Q 3N 60P
- 1Q 2N 65P
- 1Q 1N 70P
- 1Q 75P
- 10D
- 9D 2N
- 9D 1N 5P
- 9D 10P
- 8D 4N
- 8D 3N 5P
- 8D 2N 10P
- 8D 1N 15P
- 8D 20P
- 7D 6N
- 7D 5N 5P
- 7D 4N 10P
- 7D 3N 15P
- 7D 2N 20P
- 7D 1N 25P
- 7D 30P
- 6D 8N
- 6D 7N 5P
- 6D 6N 10P
- 6D 5N 15P
- 6D 4N 20P
- 6D 3N 25P
- 6D 2N 30P
- 6D 1N 35P
- 6D 40P
- 5D 10N
- 5D 9N 5P
- 5D 8N 10P
- 5D 7N 15P
- 5D 6N 20P
- 5D 5N 25P
- 5D 4N 30P
- 5D 3N 35P
- 5D 2N 40P
- 5D 1N 45P
- 5D 50P
- 4D 12N
- 4D 11N 5P
- 4D 10N 10P
- 4D 9N 15P
- 4D 8N 20P
- 4D 7N 25P
- 4D 6N 30P
- 4D 5N 35P
- 4D 4N 40P
- 4D 3N 45P
- 4D 2N 50P
- 4D 1N 55P
- 4D 60P
- 3D 14N
- 3D 13N 5P
- 3D 12N 10P
- 3D 11N 15P
- 3D 10N 20P
- 3D 9N 25P
- 3D 8N 30P
- 3D 7N 35P
- 3D 6N 40P
- 3D 5N 45P
- 3D 4N 50P
- 3D 3N 55P
- 3D 2N 60P
- 3D 1N 65P
- 3D 70P
- 2D 16N
- 2D 15N 5P
- 2D 14N 10P
- 2D 13N 15P
- 2D 12N 20P
- 2D 11N 25P
- 2D 10N 30P
- 2D 9N 35P
- 2D 8N 40P
- 2D 7N 45P
- 2D 6N 50P
- 2D 5N 55P
- 2D 4N 60P
- 2D 3N 65P
- 2D 2N 70P
- 2D 1N 75P
- 2D 80P
- 1D 18N
- 1D 17N 5P
- 1D 16N 10P
- 1D 15N 15P
- 1D 14N 20P
- 1D 13N 25P
- 1D 12N 30P
- 1D 11N 35P
- 1D 10N 40P
- 1D 9N 45P
- 1D 8N 50P
- 1D 7N 55P
- 1D 6N 60P
- 1D 5N 65P
- 1D 4N 70P
- 1D 3N 75P
- 1D 2N 80P
- 1D 1N 85P
- 1D 90P
- 20N
- 19N 5P
- 18N 10P
- 17N 15P
- 16N 20P
- 15N 25P
- 14N 30P
- 13N 35P
- 12N 40P
- 11N 45P
- 10N 50P
- 9N 55P
- 8N 60P
- 7N 65P
- 6N 70P
- 5N 75P
- 4N 80P
- 3N 85P
- 2N 90P
- 1N 95P
- 100P
WHEW!!!