

A247646


Irregular triangle read by rows, arising in enumeration of lattice paths in strips.


1



1, 1, 3, 3, 1, 1, 3, 9, 5, 7, 11, 1, 3, 9, 15, 12, 10, 9, 3, 1, 1, 1, 3, 9, 15, 27, 16, 20, 12, 14, 3, 3, 1, 1
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OFFSET

0,3


COMMENTS

It would be nice to have a more explicit definition.


LINKS

Table of n, a(n) for n=0..33.
Johann Cigler, Some remarks and conjectures related to lattice paths in strips along the xaxis, arXiv:1501.04750.


EXAMPLE

Triangle begins:
1,
1,3,3,1,
1,3,9,5,7,11,
1,3,9,15,12,10,9,3,1,1,
1,3,9,15,27,16,20,12,14,3,3,1,1,
...


CROSSREFS

The diagonals on the left are given by A247643.
Sequence in context: A160324 A197928 A109439 * A133333 A296523 A171876
Adjacent sequences: A247643 A247644 A247645 * A247647 A247648 A247649


KEYWORD

nonn,tabf,more


AUTHOR

N. J. A. Sloane, Sep 23 2014


STATUS

approved



