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Search: id:A098482
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| A098482 |
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Expansion of 1/sqrt((1-x)^2-4x^4). |
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+0
4
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| 1, 1, 1, 1, 3, 7, 13, 21, 37, 73, 147, 283, 531, 1007, 1953, 3817, 7423, 14371, 27877, 54333, 106189, 207585, 405743, 793719, 1554889, 3049525, 5984803, 11751067, 23086695, 45388291, 89289765, 175746797, 346077153, 681795925, 1343790319
(list; graph; listen)
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OFFSET
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0,5
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COMMENT
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1/sqrt((1-x)^2-4rx^4) expands to sum{k=0..floor(n/2), binomial(n-2k,k)binomial(n-3k,k)r^k}
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FORMULA
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a(n)=sum{k=0..floor(n/2), binomial(n-2k, k)binomial(n-3k, k)}
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MAPLE
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seq(add(binomial(n-3*k, k)*binomial(n-2*k, k), k=0..floor(n/3)), n=0..34); - Zerinvary Lajos (zerinvarylajos(AT)yahoo.com), Apr 03 2007
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CROSSREFS
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Cf. A098479, A098483, A098484.
Sequence in context: A098575 A138035 A032606 this_sequence A147432 A018367 A146369
Adjacent sequences: A098479 A098480 A098481 this_sequence A098483 A098484 A098485
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KEYWORD
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easy,nonn
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AUTHOR
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Paul Barry (pbarry(AT)wit.ie), Sep 10 2004
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