OFFSET
0,5
FORMULA
a(n)=-2*{0,a(n-2),0}+3*{-2/3,a(n-1)}+3*{a(n-1),-2/2}.
EXAMPLE
{1},
{1, 1},
{1, 4, 1},
{1, 13, 13, 1},
{1, 40, 70, 40, 1},
{1, 121, 304, 304, 121, 1},
{1, 364, 1195, 1684, 1195, 364, 1},
{1, 1093, 4435, 8029, 8029, 4435, 1093, 1},
{1, 3280, 15856, 35002, 44806, 35002, 15856, 3280, 1},
{1, 9841, 55222, 143704, 223366, 223366, 143704, 55222, 9841, 1},
{1, 29524, 188629, 565066, 1031206, 1250584, 1031206, 565066, 188629, 29524, 1}
MATHEMATICA
Clear[a]; a[0] = {1}; a[1] = {1, 1};
a[n_] := a[n] = -2*Join[{0}, a[n - 2], {0}] + 3*Join[{-2/3}, a[n - 1]] + 3*Join[a[n - 1], {-2/3}];
Table[a[n], {n, 0, 10}] Flatten[%]
CROSSREFS
KEYWORD
AUTHOR
Roger L. Bagula, Dec 09 2008
STATUS
approved