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Search: id:A103821
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| A103821 |
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A Whitney transform of the central binomial coefficients A000984. |
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+0
1
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| 1, 3, 11, 43, 179, 771, 3395, 15171, 68515, 311907, 1428835, 6578531, 30414435, 141105251, 656588899, 3063038051, 14321092195, 67088405091, 314825048675, 1479654425187, 6963888239203, 32815960756835, 154813864252003
(list; graph; listen)
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OFFSET
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0,2
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COMMENT
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Partial sums of A006139. The Whitney transform maps the sequence with g.f. g(x) to that with g.f. (1/(1-x))g(x(1+x)).
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FORMULA
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G.f. : 1/((1-x)sqrt(1-4x-4x^2)); a(n)=sum{k=0..n, sum{i=0..n, C(k, i-k)}*C(2k, k)}.
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CROSSREFS
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Adjacent sequences: A103818 A103819 A103820 this_sequence A103822 A103823 A103824
Sequence in context: A026671 A026876 A059278 this_sequence A049184 A049169 A049175
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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), Feb 16 2005
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