Soln2_v3 - 1 2 Note that sum converges quickly(see computer...

Note that sum
converges quickly
(see computer solu7on
next page)
# 1
# 2

A @ n_ D : =
- Sum @ If @ i ã 0 && j ã 0 && k ã 0, 0, H - 1 L ^ H i + j + k L ê Sqrt @ i^2 + j^2 + k^2 DD ,
8 i, - H n - 1 L , H n - 1 L< , 8 j, - H n - 1 L , H n - 1 L< , 8 k, - H n - 1 L , H n - 1 L<D -
3 * Sum @ H - 1 L ^ H i + j + n L ê Sqrt @ i^2 + j^2 + n^2 D ,
8 i, - H n - 1 L , H n - 1 L< , 8 j, - H n - 1 L , H n - 1 L<D -
3 * Sum @ H - 1 L ^ H i L ê Sqrt @ i^2 + 2 * n^2 D , 8 i, - H n - 1 L , H n - 1 L<D - H - 1 L ^n ê Sqrt @ 3 D ê n
N @ A @ 1 DD
- 1.45603
N @ A @ 2 DD
- 1.75177
N @ A @ 3 DD
- 1.74704
N @ A @ 4 DD
- 1.74772
N @ A @ 5 DD
- 1.7475
ListPlot @ Table @ N @ A @ n DD ,