|
| |
|
|
A098335
|
|
Expansion of 1/sqrt(1-4x+8x^2).
|
|
2
| |
|
|
1, 2, 2, -4, -26, -68, -76, 184, 1222, 3308, 3772, -9656, -64676, -177448, -203992, 536176, 3607622, 9968972, 11510636, -30723416, -207302156, -575382392, -666187432, 1796105744, 12142184476, 33803271032
(list; graph; refs; listen; history; internal format)
|
|
|
|
OFFSET
| 0,2
|
|
|
COMMENTS
| Central coefficients of (1+2x-x^2)^n. Binomial transform of A098331.
|
|
|
REFERENCES
| Tony D. Noe, On the Divisibility of Generalized Central Trinomial Coefficients, Journal of Integer Sequences, Vol. 9 (2006), Article 06.2.7.
|
|
|
FORMULA
| E.g.f. : exp(2x)BesselI(0, 2*I*x), I=sqrt(-1); a(n)=sum{k=0..floor(n/2), binomial(n, k)binomial(n-k, k)2^n(-4)^(-k)}.
a(n)=sum{k=0..floor(n/2), binomial(n, k)binomial(2(n-k), k)(-2)^k} - Paul Barry (pbarry(AT)wit.ie), Sep 08 2004
|
|
|
CROSSREFS
| Sequence in context: A176161 A006829 A154594 * A049147 A189879 A189870
Adjacent sequences: A098332 A098333 A098334 * A098336 A098337 A098338
|
|
|
KEYWORD
| easy,sign
|
|
|
AUTHOR
| Paul Barry (pbarry(AT)wit.ie), Sep 03 2004
|
| |
|
|
