|
Search: id:A098479
|
|
|
| A098479 |
|
Expansion of 1/sqrt((1-x)^2-4x^3). |
|
+0
6
|
|
| 1, 1, 1, 3, 7, 13, 27, 61, 133, 287, 633, 1407, 3121, 6943, 15517, 34755, 77959, 175213, 394499, 889461, 2007963, 4538485, 10269247, 23258881, 52726599, 119627977, 271624315, 617180533, 1403272799, 3192557561, 7267485523, 16552454205
(list; graph; listen)
|
|
|
OFFSET
|
0,4
|
|
|
COMMENT
|
1/sqrt((1-x)^2-4rx^3) expands to sum{k=0..floor(n/2), binomial(n-k,k)binomial(n-2k,k)r^k}
Hankel transform is A120580. [From Paul Barry (pbarry(AT)wit.ie), Sep 19 2008]
|
|
FORMULA
|
a(n)=sum{k=0..floor(n/2), binomial(n-k, k)binomial(n-2k, k)}
|
|
CROSSREFS
|
Cf. A098480, A098481.
Sequence in context: A068673 A140465 A080241 this_sequence A119445 A146904 A146432
Adjacent sequences: A098476 A098477 A098478 this_sequence A098480 A098481 A098482
|
|
KEYWORD
|
easy,nonn
|
|
AUTHOR
|
Paul Barry (pbarry(AT)wit.ie), Sep 10 2004
|
|
|
Search completed in 0.002 seconds
|
