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Mirror of the triangle A193821.
4

%I #6 Mar 30 2012 18:57:38

%S 1,1,1,3,3,2,9,9,8,4,27,27,26,20,8,81,81,80,72,48,16,243,243,242,232,

%T 192,112,32,729,729,728,716,656,496,256,64,2187,2187,2186,2172,2088,

%U 1808,1248,576,128,6561,6561,6560,6544,6432,5984,4864,3072,1280,256

%N Mirror of the triangle A193821.

%C A193822 is obtained by reversing the rows of the triangle A193821.

%F Write w(n,k) for the triangle at A193821. The triangle at A193822 is then given by w(n,n-k).

%e First six rows:

%e 1

%e 1....1

%e 3....3....2

%e 9....9....8.....4

%e 27...27...26....20...8

%e 81...81...80....72...48...16

%t p[n_, x_] := (a*x + b)^n

%t q[0, x_] := 1

%t q[n_, x_] := x*q[n - 1, x] + 1; q[n_, 0] := q[n, x] /. x -> 0;

%t t[n_, k_] := Coefficient[p[n, x], x^k]; t[n_, 0] := p[n, x] /. x -> 0;

%t w[n_, x_] := Sum[t[n, k]*q[n + 1 - k, x], {k, 0, n}]; w[-1, x_] := 1

%t g[n_] := CoefficientList[w[n, x], {x}]

%t TableForm[Table[Reverse[g[n]], {n, -1, z}]]

%t Flatten[Table[Reverse[g[n]], {n, -1, z}]] (* A193821 *)

%t TableForm[Table[g[n], {n, -1, z}]]

%t Flatten[Table[g[n], {n, -1, z}]] (* A193822 *)

%Y Cf. A193722, A193821.

%K nonn,tabl

%O 0,4

%A _Clark Kimberling_, Aug 06 2011

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Last modified September 23 03:49 EDT 2024. Contains 376142 sequences. (Running on oeis4.)