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A038003
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Odd Catalan numbers; more precisely, A000108(2^n-1).
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21
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OFFSET
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0,3
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COMMENTS
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LINKS
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FORMULA
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a(n) = binomial(2^(n+1)-2, 2^n-1)/(2^n).
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MATHEMATICA
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Select[CatalanNumber[Range[0, 300]], OddQ] (* Harvey P. Dale, Feb 22 2016 *)
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PROG
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(Python)
from __future__ import division
for n in range(2, 10**5+1):
....c = (c*(4*n-2))//(n+1)
....if n == s:
(PARI) a(n) = binomial(2^(n+1)-2, 2^n-1)/(2^n); \\ Joerg Arndt, Nov 05 2015
(Magma) [Binomial(2^(n+1)-2, 2^n-1)/(2^n): n in [0..10]]; // Vincenzo Librandi, Nov 01 2016
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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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