

A180900


Number of sequences of n integers p(i) i=0..n1 with 0 <= p(i) <= 4*i and p(i)  p(i1) <= 4.


1



1, 5, 35, 265, 2100, 17075, 141246, 1182719, 9994086, 85049639, 727865758, 6257933219, 54010196582, 467657712902, 4060558796894, 35341693437365, 308249001184768, 2693524485431382, 23575195919671458, 206647076624751357
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OFFSET

1,2


COMMENTS

Paths down an nhigh rectangulargrid right triangle with interior neighbor fanout 2*4 + 1.
Column 4 of A180906.
Alternatively, this sequence corresponds to the number of nonnegative walks with n steps {4,3,2,1,0,1,2,3,4} starting at the origin, ending at any altitude, and not going below the xaxis.  David Nguyen, Dec 01 2016


LINKS

R. H. Hardin, Table of n, a(n) for n=1..100
C. Banderier, C. Krattenthaler, A. Krinik, D. Kruchinin, V. Kruchinin, D. Nguyen, and M. Wallner, Explicit formulas for enumeration of lattice paths: basketball and the kernel method, arXiv:1609.06473 [math.CO], 2016.


CROSSREFS

Sequence in context: A196661 A104532 A292839 * A087630 A084135 A229111
Adjacent sequences: A180897 A180898 A180899 * A180901 A180902 A180903


KEYWORD

nonn


AUTHOR

R. H. Hardin, Sep 23 2010


STATUS

approved



