OFFSET
0,2
FORMULA
G.f.: 1/((1 - 2*x)(1 - 7*x*y)). - Ilya Gutkovskiy, Jun 03 2017
EXAMPLE
[ 1 ]
[ 2, 7 ]
[ 4, 14, 49 ]
[ 8, 28, 98, 343 ]
...
CROSSREFS
KEYWORD
AUTHOR
STATUS
approved