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A137378
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Triangle of the coefficient [x^k] of the polynomial 2^n*s_n(x) generated by exp(x*(1 - sqrt(1+t^2))/t) = sum_{n>=0} s_n(x)*t^k/k! in row n, column k.
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1
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1, 0, -1, 0, 0, 1, 0, 6, 0, -1, 0, 0, -24, 0, 1, 0, -240, 0, 60, 0, -1, 0, 0, 1800, 0, -120, 0, 1, 0, 25200, 0, -7560, 0, 210, 0, -1, 0, 0, -282240, 0, 23520, 0, -336, 0, 1, 0, -5080320, 0, 1693440, 0, -60480, 0, 504, 0, -1, 0, 0, 76204800, 0, -7257600, 0, 136080, 0, -720, 0, 1
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OFFSET
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0,8
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COMMENTS
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Row sums are: 1, -1, 1, 5, -23, -181, 1681, 17849, -259055, -3446857, 69082561,..
Weisstein uses the nomenclature "Mott Polynomial" for s_n(x), although his definition differs from Mott's by signs. - R. J. Mathar, Oct 03 2013
Also the Bell transform of the sequence defined below in the Maple program. For the definition of the Bell transform see A264428. - Peter Luschny, Jan 27 2016
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LINKS
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FORMULA
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p(x) = Exp[x*(1 - Sqrt[1 + t^2])/t]; weights 2^n*n!;
M(n,x) = n!/2^n *sum_{m=floor((n+1)/2)..n} ((-1)^m *(2*m-n) *binomial(n-1,m-1) *x^(2*m-n))/(m*(2*m-n)!). [Dmitry Kruchinin Mar 24 2013]
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EXAMPLE
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1;
0, -1;
0, 0, 1;
0, 6, 0, -1;
0, 0, -24, 0, 1;
0, -240,0, 60, 0, -1;
0, 0, 1800, 0, -120, 0, 1;
0, 25200, 0, -7560, 0, 210, 0, -1;
0, 0, -282240, 0, 23520, 0, -336, 0, 1;
0, -5080320, 0, 1693440, 0, -60480, 0, 504, 0, -1;
0, 0, 76204800, 0, -7257600, 0, 136080, 0, -720, 0, 1;
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MAPLE
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# The function BellMatrix is defined in A264428.
BellMatrix(n -> `if`(n::odd, 0, (-1)^(1+n/2)*(n+1)/(n/2+1)*(n!/(n/2)!)^2), 9); # Peter Luschny, Jan 27 2016
local m ;
if n =0 and k =0 then
1;
elif type(n+k, 'odd') then
0;
else
m := (n+k)/2 ;
(-1)^m*k*binomial(n-1, m-1)/m/k! ;
%*n! ;
end if;
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MATHEMATICA
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p[t_] = Exp[x*(1 - Sqrt[1 + t^2])/t]; Table[ ExpandAll[2^(n)*n! * SeriesCoefficient[ Series[p[t], {t, 0, 30}], n]], {n, 0, 10}]; a = Table[ CoefficientList[2^(n)*n!*SeriesCoefficient[ Series[p[t], {t, 0, 30}], n], x], {n, 0, 10}]; Flatten[a]
(* Second program: *)
BellMatrix[f_, len_] := With[{t = Array[f, len, 0]}, Table[BellY[n, k, t], {n, 0, len - 1}, {k, 0, len - 1}]];
B = BellMatrix[Function[n, If[OddQ[n], 0, (-1)^(1 + n/2)*(n + 1)/(n/2 + 1)*(n!/(n/2)!)^2]], rows = 12];
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PROG
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(Maxima)
M(n):=n!*sum(((2*m-n)*(-1)^(m)*binomial(n-1, m-1)*x^(2*m-n)/((2*m-n)!*(m))), m, floor((n+1)/2), n);
for n:0 thru 7 do if n=0 then print([1]) else (LL:makelist(coeff(ratsimp(M(n)), x, k), k, 0, n), print(LL)); // Dmitry Kruchinin, Mar 24 2013
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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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