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A201686
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a(n) = binomial(n, [n/2]) - 2.
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0
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-1, -1, 0, 1, 4, 8, 18, 33, 68, 124, 250, 460, 922, 1714, 3430, 6433, 12868, 24308, 48618, 92376, 184754, 352714, 705430, 1352076, 2704154, 5200298, 10400598, 20058298, 40116598, 77558758, 155117518, 300540193, 601080388, 1166803108, 2333606218, 4537567648, 9075135298, 17672631898, 35345263798, 68923264408, 137846528818
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OFFSET
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0,5
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LINKS
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FORMULA
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Conjecture: +(n+1)*a(n) +2*(-n-1)*a(n-1) +(-3*n+7)*a(n-2) +2*(4*n-9)*a(n-3) +4*(-n+3)*a(n-4)=0. - R. J. Mathar, Jul 17 2014
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MATHEMATICA
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Table[Binomial[n, Floor[n/2]]-2, {n, 0, 40}] (* Harvey P. Dale, Apr 12 2018 *)
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CROSSREFS
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KEYWORD
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sign
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AUTHOR
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STATUS
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approved
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