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A184937
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a(n) = binomial(2n, n) + binomial(2n-1, n-1) + binomial(2n+1, n).
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1
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3, 6, 19, 65, 231, 840, 3102, 11583, 43615, 165308, 629850, 2410226, 9256534, 35659200, 137733660, 533216475, 2068423695, 8037976980, 31285334850, 121941160110, 475898730450
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OFFSET
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0,1
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LINKS
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FORMULA
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G.f.: 1/2 - 1/(2*x) + (1+3*x)/(2*x*sqrt(1-4*x)).
(6 + 12*n)*a(n) + (7 + n)*a(1 + n) + (-3 - n)*a(n + 2) = 0. (End)
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MAPLE
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A184937 := proc(n) binomial(2*n, n)+binomial(2*n-1, n-1)+binomial(2*n+1, n) ; end proc: # R. J. Mathar, Jan 04 2011
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MATHEMATICA
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Table[Binomial[2 n, n] + Binomial[2 n - 1, n - 1] + Binomial[2 n + 1, n], {n, 0, 20}]
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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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