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A027436
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f(x) = Sum a(n)*x^n, n = 1..inf satisfies f(f(x)) = x*(1 + 4*x).
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7
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0, 1, 2, -4, 16, -80, 432, -2304, 10944, -35328, -74112, 2736384, -30853632, 238663680, -1247457280, 2201247744, 32530722816, -320650199040, 156266184704, 18314630348800, -20667999748096, -3428200020508672
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OFFSET
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0,3
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LINKS
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FORMULA
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T(n,m) = if n=m then 1 else (binomial(m,n-m)*4^(n-m)-sum(i=m+1..n-1, T(n,i)*T(i,m)))/2. a(n) = T(n,1). - Vladimir Kruchinin, Nov 08 2011
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CROSSREFS
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KEYWORD
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sign
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AUTHOR
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EXTENSIONS
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STATUS
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approved
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