A168291 T(n,k) = 4*A046802(n+1,k+1) - 2*A008518(n,k) - A007318(n,k), triangle read by rows (0 <= k <= n).
1, 1, 1, 1, 6, 1, 1, 15, 15, 1, 1, 32, 82, 32, 1, 1, 65, 330, 330, 65, 1, 1, 130, 1159, 2304, 1159, 130, 1, 1, 259, 3801, 13195, 13195, 3801, 259, 1, 1, 516, 12016, 67316, 117170, 67316, 12016, 516, 1, 1, 1029, 37212, 319332, 889230, 889230, 319332, 37212
Offset: 0
Examples
Triangle begins: 1; 1, 1; 1, 6, 1; 1, 15, 15, 1; 1, 32, 82, 32, 1; 1, 65, 330, 330, 65, 1; 1, 130, 1159, 2304, 1159, 130, 1; 1, 259, 3801, 13195, 13195, 3801, 259, 1; 1, 516, 12016, 67316, 117170, 67316, 12016, 516, 1; ... reformatted. - _Franck Maminirina Ramaharo_, Oct 21 2018
Crossrefs
Programs
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Maxima
A123125(n, k) := sum((-1)^(k - j)*(binomial(n - j, k - j))*stirling2(n, j)*j!, j, 0, k)$ A046802(n, k) := sum(binomial(n - 1, r)*A123125(r, k - 1), r, k - 1, n - 1)$ A008518(n, k) := A123125(n, k) + A123125(n, k + 1)$ T(n, k) := 4*A046802(n + 1, k + 1) - 2*A008518(n, k) - binomial(n, k)$ create_list(T(n, k), n, 0, 10, k, 0, n); /* Franck Maminirina Ramaharo, Oct 21 2018 */
Formula
E.g.f.: 4*(1 - x)*exp(t)/(1 - x*exp(t*(1 - x))) - 2*(exp(t) - x*exp(t*x))/(exp(t*x) - x*exp(t)) - exp(t*(1 + x)).
Extensions
Edited, new name by Franck Maminirina Ramaharo, Oct 21 2018