login
Triangle of numbers where T(n,k) is the number of k-dimensional faces on a partially truncated n-cube, 0 <= k <= n.
2

%I #9 Apr 05 2016 01:02:59

%S 1,2,1,8,8,1,24,36,14,1,64,128,88,24,1,160,400,400,200,42,1,384,1152,

%T 1520,1120,444,76,1,896,3136,5152,5040,2968,980,142,1,2048,8192,16128,

%U 19712,15456,7616,2160,272,1,4608,20736,47616,69888,68544,45024,19104,4752,530,1,10240,51200,134400,230400,271488,223104,126240,47040,10420,1044,1

%N Triangle of numbers where T(n,k) is the number of k-dimensional faces on a partially truncated n-cube, 0 <= k <= n.

%H Wikipedia, <a href="https://en.wikipedia.org/wiki/Truncated_cube">Truncated cube</a>

%F G.f. for rows (n > 0): (x+2)^n + 2^n*(x+1)*((x+1)^(n-1)-1)/x.

%F O.g.f: 1 + 1/(1-(x+2)*y) + 1/(x*(1-2*y*(x+1))) - (x+1)/(x*(1-2*y)).

%F E.g.f: 1 + exp((x+2)*z) + (exp(2*z*(x+1))-(x+1)*exp(2*z))/x.

%e Triangle begins:

%e 1;

%e 2, 1;

%e 8, 8, 1;

%e 24, 36, 14, 1;

%e 64, 128, 88, 24, 1;

%e ...

%e Row 2 describes an octagon: 8 vertices and 8 edges.

%e Row 3 describes a truncated cube: 24 vertices, 36 edges, and 14 faces.

%t Flatten[Table[

%t CoefficientList[

%t D[1 + Exp[(x + 2) z] + ( Exp[2 z (x + 1)] - (x + 1) Exp[2 z])/x, {z,

%t k}] /. z -> 0, x], {k, 0, 10}]]

%Y Cf. A038207 (n-cube).

%K nonn,tabl

%O 0,2

%A _Vincent J. Matsko_, Apr 03 2016