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A107725 Column 0 of A107724, which is the matrix logarithm of triangle A107719. 1
0, 1, 4, 31, 343, 4855, 83209, 1670743, 38436673, 996825703, 28778874481, 915636860023, 31837734460129, 1201360385000071, 48899006799783889, 2135779996980897175, 99646497213608842561, 4946194601237466540967 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,3

LINKS

Table of n, a(n) for n=0..17.

PROG

(PARI) {a(n)=local(L, M=matrix(n+1, n+1, m, j, if(m>=j, if(m==j, 1, if(m==j+1, -3*j, polcoeff(1/sum(i=0, m-j, prod(r=0, i-1, 3*r+1)*x^i)+O(x^m), m-j)))))^-1); L=sum(i=1, #M, (-1)^(i-1)*(M-M^0)^i/i); return(if(n<0, 0, L[n+1, 1]/3))}

CROSSREFS

Cf. A107717, A107719, A107724.

Sequence in context: A076280 A141005 A122400 * A145160 A129271 A136728

Adjacent sequences:  A107722 A107723 A107724 * A107726 A107727 A107728

KEYWORD

nonn

AUTHOR

Paul D. Hanna, May 30 2005

STATUS

approved

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Last modified March 6 20:37 EST 2021. Contains 341850 sequences. (Running on oeis4.)