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A134635 Row sums of triangle A134634. 1
1, 2, 6, 18, 54, 164, 508, 1610, 5222, 17308, 58484, 200948, 700348, 2470472, 8804024, 31648858, 114623366, 417820972, 1531629764, 5642508508, 20878731476, 77561756152, 289156105544, 1081466311108, 4056621689564, 15257327887384, 57525469116168, 217383333920040, 823195469508792, 3123379468819600, 11872247508521072, 45203794091311354 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,2

REFERENCES

N. Arbesfeld, Partial permutations avoiding pairs of patterns, Discrete Math., 313 (2013), 2614-2625.

LINKS

Table of n, a(n) for n=0..31.

FORMULA

Conjecture: (n+1)*a(n) +(-7*n+1)*a(n-1) +2*(7*n-8)*a(n-2) +4*(-2*n+5)*a(n-3)=0. - R. J. Mathar, May 30 2014

EXAMPLE

a(3) = 18 = sum of row 3 terms of triangle A134634: (5 + 4 + 4 + 5).

CROSSREFS

Cf. A134634.

Sequence in context: A179362 A025192 A008776 * A192338 A114464 A062415

Adjacent sequences:  A134632 A134633 A134634 * A134636 A134637 A134638

KEYWORD

nonn

AUTHOR

Gary W. Adamson, Nov 04 2007

EXTENSIONS

Corrected and extended by N. J. A. Sloane, Feb 18 2013

STATUS

approved

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Last modified December 7 21:15 EST 2016. Contains 278895 sequences.