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A348530
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a(1) = 1; a(n) = Sum_{k=1..ceiling(n/2)} a(k) * a(n-k).
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1
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1, 1, 2, 3, 7, 14, 33, 70, 173, 400, 1008, 2391, 6132, 15019, 38799, 96520, 252022, 638788, 1679091, 4297452, 11373921, 29426350, 78204705, 203658812, 543828898, 1426912159, 3822817135, 10078227662, 27092960887, 71803114869, 193496832857, 514684042158
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OFFSET
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1,3
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LINKS
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MAPLE
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a:= proc(n) option remember; `if`(n=1, 1,
add(a(k)*a(n-k), k=1..ceil(n/2)))
end:
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MATHEMATICA
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a[1] = 1; a[n_] := a[n] = Sum[a[k] a[n - k], {k, 1, Ceiling[n/2]}]; Table[a[n], {n, 1, 32}]
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CROSSREFS
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KEYWORD
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nonn
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AUTHOR
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STATUS
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approved
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