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Search: id:A143603
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| A143603 |
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Triangle, read by rows, such that the g.f. of column k = G(x)^(2k+1) where G(x) = 1 + x*G(x)^3 is the g.f. of A001764 (ternary trees). |
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+0
1
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| 1, 1, 1, 3, 3, 1, 12, 12, 5, 1, 55, 55, 25, 7, 1, 273, 273, 130, 42, 9, 1, 1428, 1428, 700, 245, 63, 11, 1, 7752, 7752, 3876, 1428, 408, 88, 13, 1, 43263, 43263, 21945, 8379, 2565, 627, 117, 15, 1, 246675, 246675, 126500, 49588, 15939, 4235, 910, 150, 17, 1
(list; table; graph; listen)
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OFFSET
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1,4
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FORMULA
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T(n,k) = C(3n-k,n-k)*(2k+1)/(2n+1) for 0<=k<=n.
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EXAMPLE
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Triangle begins:
1;
1, 1;
3, 3, 1;
12, 12, 5, 1;
55, 55, 25, 7, 1;
273, 273, 130, 42, 9, 1;
1428, 1428, 700, 245, 63, 11, 1;
7752, 7752, 3876, 1428, 408, 88, 13, 1; ...
where g.f. of column k = G(x)^(2k+1) where G(x) = 1 + x*G(x)^3.
Matrix inverse begins:
1;
-1, 1;
0, -3, 1;
0, 3, -5, 1;
0, -1, 10, -7, 1;
0, 0, -10, 21, -9, 1;
0, 0, 5, -35, 36, -11, 1;
0, 0, -1, 35, -84, 55, -13, 1; ...
where g.f. of column k = (1-x)^(2k+1) for k>=0.
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PROGRAM
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(PARI) {T(n, k)=binomial(3*n-k, n-k)*(2*k+1)/(2*n+1)}
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CROSSREFS
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Cf. columns: A001764, A102893, A102594; row sums: A006013.
Sequence in context: A050609 A120870 A010029 this_sequence A094021 A062746 A115193
Adjacent sequences: A143600 A143601 A143602 this_sequence A143604 A143605 A143606
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KEYWORD
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nonn,tabl
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AUTHOR
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Paul D. Hanna (pauldhanna(AT)juno.com), Aug 29 2008
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