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A107718 Column 1 of triangle A107717. 1
1, 6, 57, 723, 11361, 212151, 4584081, 112480887, 3090105921, 93988998183, 3136338148017, 113945190405303, 4477940877230625, 189296643095867847, 8565988634172222609, 413169192012610306263, 21161884092470464784385 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,2

COMMENTS

Equals one-half of column 0 of A107719 shift 1 place left.

LINKS

Table of n, a(n) for n=0..16.

PROG

(PARI) {a(n)=if(n<0, 0, (matrix(n+2, n+2, 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)[n+2, 2])}

CROSSREFS

Cf. A107717, A107719.

Sequence in context: A306030 A152170 A087659 * A308863 A000406 A305276

Adjacent sequences:  A107715 A107716 A107717 * A107719 A107720 A107721

KEYWORD

nonn

AUTHOR

Paul D. Hanna, May 30 2005

STATUS

approved

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Last modified April 6 16:14 EDT 2020. Contains 333276 sequences. (Running on oeis4.)