|
Search: id:A099526
|
|
|
| A099526 |
|
Expansion of 1/(1-2x-3x^4). |
|
+0
1
|
|
| 1, 2, 4, 8, 19, 44, 100, 224, 505, 1142, 2584, 5840, 13195, 29816, 67384, 152288, 344161, 777770, 1757692, 3972248, 8976979, 20287268, 45847612, 103611968, 234154873, 529171550, 1195885936, 2702607776, 6107680171, 13802874992
(list; graph; listen)
|
|
|
OFFSET
|
0,2
|
|
|
COMMENT
|
In general 1/(1-a*x-b*x^4) expands to sum{k=0..floor(n/4),C(n-3k,k)b^(n-3k)(a/b)^(n-4k)}.
|
|
FORMULA
|
a(n)=2a(n-1)+3a(n-4); a(n)=sum{k=0..floor(n/4), binomial(n-3k, k)3^(n-3k)(2/3)^(n-4k)}.
|
|
CROSSREFS
|
Cf. A099525.
Sequence in context: A139784 A037444 A151526 this_sequence A005703 A003081 A100133
Adjacent sequences: A099523 A099524 A099525 this_sequence A099527 A099528 A099529
|
|
KEYWORD
|
easy,nonn
|
|
AUTHOR
|
Paul Barry (pbarry(AT)wit.ie), Oct 20 2004
|
|
|
Search completed in 0.004 seconds
|
