A193892 - OEIS

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A193892

Mirror of the triangleA193891.

2

1, 2, 1, 8, 5, 2, 20, 14, 8, 3, 40, 30, 20, 11, 4, 70, 55, 40, 26, 14, 5, 112, 91, 70, 50, 32, 17, 6, 168, 140, 112, 85, 60, 38, 20, 7, 240, 204, 168, 133, 100, 70, 44, 23, 8, 330, 285, 240, 196, 154, 115, 80, 50, 26, 9, 440, 385, 330, 276, 224, 175, 130, 90, 56

(list; table; graph; refs; listen; history; text; internal format)

OFFSET

0,2

COMMENTS

A193892is obtained by reversing the rows of the triangleA193891.

LINKS

Table of n, a(n) for n=0..63.

FORMULA

Write w(n,k) for the triangle atA193891.The triangle atA193892is then given by w(n,n-k).

EXAMPLE

First six rows:

1

2....1

8....5....2

20...14...8....3

40...30...20...11...4

70...55...40...26...14...5

MATHEMATICA

z = 9;

p[0, x_]:= 1; p[n_, x_]:= x*p[n - 1, x] + n + 1;

q[n_, x_]:= p[n, x];

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

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

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

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

Flatten[Table[Reverse[g[n]], {n, -1, z}]] (*A193891*)

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

Flatten[Table[g[n], {n, -1, z}]] (*A193892*)

CROSSREFS

Sequence in context:A368386 A135520 A136230*A193907 A298592 A344163

Adjacent sequences:A193889 A193890 A193891*A193893 A193894 A193895

KEYWORD

nonn,tabl

AUTHOR

Clark Kimberling,Aug 08 2011

STATUS

approved