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Search: id:A103769
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| A103769 |
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Trinomial transform of central binomial coefficients A001405. |
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+0
1
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| 1, 4, 21, 123, 757, 4788, 30817, 200784, 1320093, 8740284, 58193673, 389233287, 2613338091, 17602627006, 118892784555, 804951501469, 5461228061541, 37120212399708, 252720891884473, 1723088114793535, 11763751150648785
(list; graph; listen)
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OFFSET
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0,2
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FORMULA
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a(n)=sum{k=0..2n, T(n, k)*binomial(k, floor(k/2))}, where T(n, k) is given by A027907; a(n)=sum{k=0..n, sum{j=0..n, C(n, j)C(j, k)C(j+k, floor((j+k)/2))}}.
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CROSSREFS
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Cf. A082760.
Sequence in context: A045721 A101810 A001888 this_sequence A003014 A108404 A115136
Adjacent sequences: A103766 A103767 A103768 this_sequence A103770 A103771 A103772
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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 15 2005
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