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A180907 Number of sequences of n integers p(i) i=0..n-1 with 0<=p(i)<=2*i and -2<p(i)-p(i-1)<=2 1
1, 3, 11, 42, 163, 639, 2520, 9976, 39595, 157441, 626859, 2498318, 9964308, 39764292, 158756360, 634044576, 2532959099, 10121210373, 40449588625, 161680869046, 646330342699, 2584001013295, 10331554755044, 41311180250504 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,2

COMMENTS

Paths down a n-high staggered-grid minimally right-leaning right triangle with interior neighbor fanout 2*2

Column 2 of A180915

REFERENCES

M. Wallner, Lattice Path Combinatorics, Diplomarbeit, Institut für Diskrete Mathematik und Geometrie der Technischen Universität Wien, 2013; http://dmg.tuwien.ac.at/drmota/Thesis_Wallner.pdf

LINKS

R. H. Hardin, Table of n, a(n) for n=1..100

CROSSREFS

Sequence in context: A059716 A122368 A032443 * A143464 A270561 A259858

Adjacent sequences:  A180904 A180905 A180906 * A180908 A180909 A180910

KEYWORD

nonn

AUTHOR

R. H. Hardin Sep 23 2010

STATUS

approved

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Last modified December 12 01:57 EST 2019. Contains 329948 sequences. (Running on oeis4.)