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A053022 Number of subdiagonal directed diagonally-convex animals with given diagonal semiperimeter. 0
1, 1, 3, 9, 30, 107, 396, 1506, 5848, 23087, 92381, 373830, 1527192, 6290054, 26090780, 108895558, 456992576, 1927176941, 8162557837, 34708427777, 148110582311, 634074235584, 2722547715302, 11721572763762, 50591504811439 (list; graph; refs; listen; history; text; internal format)
OFFSET

2,3

REFERENCES

F. Ibn-Majdoub-Hassani, Generating functions for directed animals convex following their direction, In: Actes du Seminaire Lotharingien de Combinatoire, 33rd session. Publication de l'IRMA, Strasbourg, France, 1994.

F. Ibn-Majdoub-Hassani, Combinatorics of polyominoes and oscillating shifted tableaux. Phd Thesis. Laboratoire de Recherche en Informatique, Univ. Paris-Sud, France, 1996

LINKS

Table of n, a(n) for n=2..26.

Seminaire Lotharingien de Combinatoire, Home page

FORMULA

G.f.: A(x)^4 + 2x(1 - x + x^2)A(x)^3 + x( - 1 + 3x - 7x^2 + 5x^3 - 2x^4 + x^5)A(x)^2 + x^3(2 - 5x + 6x^2 - 3x^3 + 2x^4)A(x) + x^5( - 1 + 2x - x^2 + x^3) = 0.

CROSSREFS

Sequence in context: A024332 A036727 A216454 * A128725 A099783 A200074

Adjacent sequences:  A053019 A053020 A053021 * A053023 A053024 A053025

KEYWORD

nonn

AUTHOR

Fouad IBN MAJDOUB HASSANI, Feb 24 2000

EXTENSIONS

More terms from Vladeta Jovovic, Mar 27 2001

STATUS

approved

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Last modified January 23 02:40 EST 2019. Contains 319365 sequences. (Running on oeis4.)