OFFSET
0,4
LINKS
Shi-Mei Ma, Qi Fang, Toufik Mansour and Yeong-Nan Yeh, Alternating Eulerian polynomials and left peak polynomials, arXiv:2104.09374 [math.CO], 2021.
EXAMPLE
Triangle begins:
1;
1, 1;
3, 2, 3;
11, 13, 13, 11;
57, 76, 118, 76, 57;
...
MATHEMATICA
Bhat[0][_] = 1; Bhat[1][x_] := 1 + x;
Bhat[n_][x_] := Bhat[n][x] = (n + x + (n-1) x^2) Bhat[n - 1][x] + (1 - x)* (1 + x^2) Bhat[n-1]'[x];
Table[CoefficientList[Bhat[n][x], x], {n, 0, 8}] // Flatten (* Jean-François Alcover, Apr 21 2021 *)
CROSSREFS
KEYWORD
nonn,tabl
AUTHOR
N. J. A. Sloane, Apr 21 2021
EXTENSIONS
More terms from Jean-François Alcover, Apr 21 2021
STATUS
approved