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A132785 Main diagonal of triangle A132784. 2
1, 1, 1, 1, 2, 7, 40, 342, 4118, 66581, 1393998, 36722251, 1189340060, 46466456210, 2155486553918, 117137645018204, 7372271485024724, 532031521606758006, 43644205623323138712, 4038679603699275061593, 418716209086799704826908 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,5

COMMENTS

Also equals (with offset) the row sums and rightmost border of triangle A132784.

LINKS

Table of n, a(n) for n=0..20.

PROG

(PARI) {a(n)=local(A=[1]); if(n==0, 1, for(i=1, n, B=Vec(Pol(A)/(1-x +x*O(x^(i*(i-1)/2)))); A=concat(vector(i), B)); A[n+1])}

CROSSREFS

Cf. A132784 (triangle), A132786 (column sums).

Sequence in context: A031973 A274279 A319945 * A224677 A064626 A137731

Adjacent sequences:  A132782 A132783 A132784 * A132786 A132787 A132788

KEYWORD

nonn

AUTHOR

Paul D. Hanna, Aug 29 2007

STATUS

approved

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Last modified January 25 07:51 EST 2020. Contains 331241 sequences. (Running on oeis4.)