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Search: id:A088927
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| A088927 |
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Antidiagonal sums of table A088925, which lists coefficients T(n,k) of x^n*y^k in f(x,y) that satisfies f(x,y) = 1/(1-x-y) + xy*f(x,y)^3. |
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+0
3
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| 1, 2, 5, 14, 43, 142, 496, 1808, 6807, 26270, 103357, 412942, 1670572, 6828824, 28159880, 116997296, 489271039, 2057800158, 8698624303, 36936288650, 157474552403, 673830974654, 2892864930292, 12457038200008, 53789813903620
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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, n, sum(i=0, k, C(n, 2i)*C(n-2i, k-i)*A001764(i) )), where A001764(i)=(3i)!/[i!(2i+1)! ] (from Michael Somos).
G.f. satisfies A(x) = 1/(1-2x) + x^2*A(x)^3.
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EXAMPLE
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A(x) = 1/(1-2x) + x^2*A(x)^3 since 1/(1-2x) = 1 + 2x + 4x^2 + 8x^3 +... and x^2*A(x)^3 = 1x^2 + 6x^3 + 27x^4 + 110x^5 +...
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CROSSREFS
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Cf. A088925 (table), A088926 (diagonal), A001764.
Sequence in context: A005317 A126566 A112808 this_sequence A110489 A005425 A035349
Adjacent sequences: A088924 A088925 A088926 this_sequence A088928 A088929 A088930
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KEYWORD
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nonn
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AUTHOR
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Paul D. Hanna (pauldhanna(AT)juno.com), Oct 23 2003
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