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A104989 Row sums of triangle A104988, which equals the matrix square of triangle A104980. 2
1, 3, 13, 69, 433, 3133, 25657, 234537, 2367825, 26176981, 314670353, 4088360569, 57112939433, 853922061413, 13609089281849, 230346936181465, 4127180489763649, 78046835384582069, 1553536327234953153 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,2

LINKS

Table of n, a(n) for n=0..18.

PROG

(PARI) {a(n)=if(n<0, 0, sum(k=0, n, (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. A104988, A104980.

Sequence in context: A196794 A184818 A007808 * A119906 A059726 A274379

Adjacent sequences:  A104986 A104987 A104988 * A104990 A104991 A104992

KEYWORD

nonn

AUTHOR

Paul D. Hanna, Apr 10 2005

STATUS

approved

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Last modified September 25 12:47 EDT 2020. Contains 337344 sequences. (Running on oeis4.)