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A049224
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A convolution triangle of numbers obtained from A025751.
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3
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1, 15, 1, 330, 30, 1, 8415, 885, 45, 1, 232254, 26730, 1665, 60, 1, 6735366, 825858, 58320, 2670, 75, 1, 202060980, 25992252, 2003562, 106560, 3900, 90, 1, 6213375135, 830282805, 68351283, 4038741, 174825, 5355, 105, 1, 194685754230
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OFFSET
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1,2
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COMMENTS
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G.f. for m-th column: ((1-(1-36*x)^(1/6))/6)^m.
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LINKS
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FORMULA
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a(n, m) = 6*(6*(n-1)-m)*a(n-1, m)/n + m*a(n-1, m-1)/n, n >= m >= 1; a(n, m) := 0, n<m; a(n, 0) := 0; a(1, 1)=1.
G.f.: [(1-(1-36*x)^(1/6))/6]^m=sum(n>=m, T(n,m)*x^n), T(n,m)=(m*sum(i=m..n, binomial(-m+2*i-1,i-1)*2^(2*n-2*i)*sum(k=0..n-i, binomial(k,n-k-i)*3^(k+i-m)*(-1)^(n-k-i)*binomial(n+k-1,n-1))))/n. - Vladimir Kruchinin, Dec 21 2011
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PROG
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(Maxima) T(n, m):=(m*sum(binomial(-m+2*i-1, i-1)*2^(2*n-2*i)*sum(binomial(k, n-k-i)*3^(k+i-m)*(-1)^(n-k-i)*binomial(n+k-1, n-1), k, 0, n-i), i, m, n))/n; /* Vladimir Kruchinin, Dec 21 2011 */
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CROSSREFS
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KEYWORD
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AUTHOR
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STATUS
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approved
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