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A104988 Matrix square of triangle A104980. 4
1, 2, 1, 8, 4, 1, 42, 20, 6, 1, 266, 120, 38, 8, 1, 1954, 836, 270, 62, 10, 1, 16270, 6616, 2150, 516, 92, 12, 1, 151218, 58576, 19030, 4688, 882, 128, 14, 1, 1551334, 573672, 185674, 46516, 9050, 1392, 170, 16, 1, 17414114, 6159976, 1982310, 502324, 99994 (list; table; graph; refs; listen; history; text; internal format)
OFFSET

0,2

COMMENTS

Triangular matrix A104980 satisfies: SHIFT_LEFT(column 0 of A104980^p) = p*(column p+1 of A104980) for p>=0.

LINKS

Table of n, a(n) for n=0..49.

FORMULA

T(n+1, 0) = 2*A104980(n+3, 3) = 2*A104982(n) for n>=0.

EXAMPLE

Triangle begins:

1;

2,1;

8,4,1;

42,20,6,1;

266,120,38,8,1;

1954,836,270,62,10,1;

16270,6616,2150,516,92,12,1;

151218,58576,19030,4688,882,128,14,1;

1551334,573672,185674,46516,9050,1392,170,16,1;

17414114,6159976,1982310,502324,99994,15956,2070,218,18,1; ...

PROG

(PARI) T(n, k)=if(n<k || k<0, 0, (matrix(n+1, n+1, m, j, if(m==j, 1, if(m==j+1, -m+1, -polcoeff((1-1/sum(i=0, m, i!*x^i))/x+O(x^m), m-j-1))))^-2)[n+1, k+1])

CROSSREFS

Cf. A104980, A104982 (column 0), A104989 (row sums).

Sequence in context: A110446 A109979 A110171 * A136225 A089460 A308695

Adjacent sequences:  A104985 A104986 A104987 * A104989 A104990 A104991

KEYWORD

nonn,tabl

AUTHOR

Paul D. Hanna, Apr 10 2005

STATUS

approved

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Last modified September 20 00:43 EDT 2020. Contains 337220 sequences. (Running on oeis4.)