|
|
A349045
|
|
G.f. A(x) satisfies: A(x) = 1 / (1 + x - 2 * x * A(-3*x)).
|
|
1
|
|
|
1, 1, -5, -101, 5293, 869269, -420787937, -614362594985, 2685998620138297, 35251053957604379689, -1387622522805833315933693, -163878220402091372424795125261, 58060742480730955957157145945031525, 61711834213019891772066352604323845604861
(list;
graph;
refs;
listen;
history;
text;
internal format)
|
|
|
OFFSET
|
0,3
|
|
LINKS
|
|
|
FORMULA
|
a(0) = 1; a(n) = -a(n-1) + 2 * Sum_{k=0..n-1} (-3)^k * a(k) * a(n-k-1).
|
|
MATHEMATICA
|
nmax = 13; A[_] = 0; Do[A[x_] = 1/(1 + x - 2 x A[-3 x]) + O[x]^(nmax + 1) // Normal, nmax + 1]; CoefficientList[A[x], x]
a[0] = 1; a[n_] := a[n] = -a[n - 1] + 2 Sum[(-3)^k a[k] a[n - k - 1], {k, 0, n - 1}]; Table[a[n], {n, 0, 13}]
|
|
CROSSREFS
|
|
|
KEYWORD
|
sign
|
|
AUTHOR
|
|
|
STATUS
|
approved
|
|
|
|