|
Search: id:A101497
|
|
|
| A101497 |
|
Expansion of (1-x^2)/(1-2x+2x^3+x^4). |
|
+0
1
|
|
| 1, 2, 3, 4, 3, -2, -15, -40, -79, -126, -157, -116, 99, 638, 1665, 3248, 5121, 6274, 4387, -4716, -27101, -69250, -133455, -207992, -250383, -164606, 220227, 1149212, 2878019, 5480190, 8441729, 9978208, 6118017, -10127614, -48653373, -119520988, -224904765, -342375170
(list; graph; listen)
|
|
|
OFFSET
|
0,2
|
|
|
COMMENT
|
Results from applying a Chebyshev transform after an inverse Catalan transform to 1/(1-2x). The inverse Catalan transform maps g(x)->g(x(1-x)) while the Chebyshev transform maps h(x)->(1/(1+x^2))h(x/(1+x^2)).
|
|
FORMULA
|
a(n)=2a(n-1)-2a(n-3)-a(n-4); a(n)=sum{k=0..floor(n/2), sum{j=0..floor((n-2k)/2), C(n-k, k)C(n-2k-j, j)2^(n-2k-j)}}.
|
|
CROSSREFS
|
Sequence in context: A134536 A131731 A111880 this_sequence A065870 A123699 A119352
Adjacent sequences: A101494 A101495 A101496 this_sequence A101498 A101499 A101500
|
|
KEYWORD
|
easy,sign
|
|
AUTHOR
|
Paul Barry (pbarry(AT)wit.ie), Dec 04 2004
|
|
|
Search completed in 0.002 seconds
|
