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Search: id:A101496
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| A101496 |
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Expansion of (1-x^2)/(1-x-x^2+x^3+x^4). |
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+0
1
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| 1, 1, 1, 1, 0, -1, -3, -5, -7, -8, -7, -3, 5, 17, 32, 47, 57, 55, 33, -16, -95, -199, -311, -399, -416, -305, -11, 499, 1209, 2024, 2745, 3061, 2573, 865, -2368, -7137, -12943, -18577, -22015, -20512, -11007, 9073, 40593, 81185, 123712, 155231, 157165, 107499, -14279, -219176
(list; graph; listen)
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OFFSET
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0,7
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COMMENT
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Results from applying a Chebyshev transform after an inverse Catalan transform to 1/(1-x). 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)).
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FORMULA
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a(n)=a(n-1)+a(n-2)-a(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)}}.
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CROSSREFS
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Sequence in context: A099726 A142340 A131979 this_sequence A008508 A036593 A086674
Adjacent sequences: A101493 A101494 A101495 this_sequence A101497 A101498 A101499
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KEYWORD
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easy,sign
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AUTHOR
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Paul Barry (pbarry(AT)wit.ie), Dec 04 2004
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