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A036908 Number of different compact source directed animals with 1 point on the bottom line. 1
1, 2, 5, 14, 40, 116, 339, 996, 2937, 8684, 25729, 76352, 226868, 674806, 2008907, 5984886, 17841024, 53212500, 158784033, 473995320, 1415449578, 4228149450, 12633596331, 37758241434, 112873961079, 337492122822, 1009283640669, 3018807519506, 9030752740042 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,2

LINKS

Harvey P. Dale, Table of n, a(n) for n = 1..1000

Nickolas Hein, Jia Huang, Variations of the Catalan numbers from some nonassociative binary operations, arXiv:1807.04623 [math.CO], 2018.

FORMULA

G.f.: x(1-3x+sqrt(1-2x-3x^2))/((1-3x)(3x-1+sqrt(1-2x-3x^2)).

MATHEMATICA

CoefficientList[Series[x (1-3x+ Sqrt[1-2x-3x^2])/((1-3x)(3x-1+ Sqrt[ 1- 2x- 3x^2])), {x, 0, 30}], x] (* Harvey P. Dale, Jun 03 2012 *)

CROSSREFS

Sequence in context: A159035 A117189 A052963 * A293346 A273900 A126220

Adjacent sequences:  A036905 A036906 A036907 * A036909 A036910 A036911

KEYWORD

nonn

AUTHOR

Louis Shapiro

EXTENSIONS

More terms from Harvey P. Dale, Jun 03 2012

STATUS

approved

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Last modified January 22 05:11 EST 2019. Contains 319353 sequences. (Running on oeis4.)