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 A156529 A triangular sequence: e(n,k)=(k + 1)e(n - 1, k) + (2n - k - 1)e(n - 1, k - 1); t(n,m)=(e(n, k)*e(n, n - k - 1)). 0

%I

%S 1,2,2,6,64,6,24,1276,1276,24,120,23088,107584,23088,120,720,422712,

%T 6388800,6388800,422712,720,5040,8156160,326165400,1031694400,

%U 326165400,8156160,5040,40320,168521184,15666814800,126099116000,126099116000

%N A triangular sequence: e(n,k)=(k + 1)e(n - 1, k) + (2n - k - 1)e(n - 1, k - 1); t(n,m)=(e(n, k)*e(n, n - k - 1)).

%C Row sums are:

%C {1, 4, 76, 2600, 154000, 13624464, 1700347600, 283868984608, 61166882025040,

%C 16525206308179712,...}

%F e(n,k)=(k + 1)e(n - 1, k) + (2n - k - 1)e(n - 1, k - 1); t(n,m)=(e(n, k)*e(n, n - k - 1))..

%e {1},

%e {2, 2},

%e {6, 64, 6},

%e {24, 1276, 1276, 24},

%e {120, 23088, 107584, 23088, 120},

%e {720, 422712, 6388800, 6388800, 422712, 720},

%e {5040, 8156160, 326165400, 1031694400, 326165400, 8156160, 5040},

%e {40320, 168521184, 15666814800, 126099116000, 126099116000, 15666814800, 168521184, 40320},

%e {362880, 3748855680, 741628668960, 13217568000000, 33240990250000, 13217568000000, 741628668960, 3748855680, 362880},

%e {3628800, 89830895040, 35494281317376, 1272445743488640, 6954573294760000, 6954573294760000, 1272445743488640, 35494281317376, 89830895040, 3628800}

%t e[n_, 0] := 1;

%t e[n_, k_] := 0 /; k >= n;

%t e[n_, k_] := (k + 1)e[n - 1, k] + (2n - k - 1)e[n - 1, k - 1];

%t Table[Table[(e[n, k]*e[n, n - k - 1]), {k, 0, n - 1}], {n, 1, 10}];

%t Flatten[%]

%Y A008517

%K nonn,tabl,uned

%O 0,2

%A _Roger L. Bagula_, Feb 09 2009

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Last modified December 3 12:33 EST 2020. Contains 338904 sequences. (Running on oeis4.)