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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
OFFSET
0,3
COMMENTS
It would be nice to have a more explicit definition.
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: A347026 A197928 A109439 * A133333 A296523 A171876
KEYWORD
nonn,tabf,more
AUTHOR
N. J. A. Sloane, Sep 23 2014
STATUS
approved