|
Search: id:A106184
|
|
|
| A106184 |
|
Expansion of 1/sqrt(1-4x-8x^2+32x^3). |
|
+0
1
|
|
| 1, 2, 10, 28, 118, 380, 1508, 5240, 20326, 73836, 284396, 1061128, 4085820, 15500120, 59820040, 229366768, 887943046, 3428967500, 13315684764, 51678099304, 201246353492, 783890932488, 3060144292600, 11953056489104
(list; graph; listen)
|
|
|
OFFSET
|
0,2
|
|
|
COMMENT
|
In general, a(n)=sum{k=0..floor(n/2), C(2k,k)C(2(n-2k),n-2k)*r^k} has g.f. 1/sqrt(1-4x-4r*x^2+16r*x^3).
|
|
FORMULA
|
a(n)=sum{k=0..floor(n/2), C(2k, k)C(2(n-2k), n-2k)*2^k}.
|
|
CROSSREFS
|
Adjacent sequences: A106181 A106182 A106183 this_sequence A106185 A106186 A106187
Sequence in context: A000900 A124023 A127921 this_sequence A076438 A101561 A047112
|
|
KEYWORD
|
easy,nonn
|
|
AUTHOR
|
Paul Barry (pbarry(AT)wit.ie), Apr 24 2005
|
|
|
Search completed in 0.002 seconds
|
