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A210543
Number of arrays of n nonnegative integers with value i>0 appearing only after i-1 has appeared at least 6 times.
4
1, 1, 1, 1, 1, 1, 2, 4, 8, 16, 32, 64, 129, 267, 582, 1364, 3454, 9338, 26429, 76929, 227579, 680113, 2050000, 6242818, 19284165, 60754153, 196341570, 654012814, 2251195713, 8005274899, 29325473071, 110181281435, 422565983725
OFFSET
1,7
FORMULA
a(n) = 1 if n<=6 else Sum_{i=0..n-6} (binomial(n-6,i)*a(i)).
EXAMPLE
Some solutions for n=17
..0....0....0....0....0....0....0....0....0....0....0....0....0....0....0....0
..0....0....0....0....0....0....0....0....0....0....0....0....0....0....0....0
..0....0....0....0....0....0....0....0....0....0....0....0....0....0....0....0
..0....0....0....0....0....0....0....0....0....0....0....0....0....0....0....0
..0....0....0....0....0....0....0....0....0....0....0....0....0....0....0....0
..0....0....0....0....0....0....0....0....0....0....0....0....0....0....0....0
..0....1....1....1....0....0....1....1....1....0....1....1....1....1....0....0
..1....0....0....1....0....1....1....1....1....1....0....1....0....1....1....1
..0....0....0....1....1....1....1....0....1....1....1....0....1....1....1....1
..1....1....1....0....0....1....0....1....1....1....1....0....1....0....1....1
..0....0....1....1....0....1....1....1....0....0....0....0....0....1....1....1
..1....1....1....1....1....1....1....1....1....1....1....1....1....1....1....0
..0....1....0....0....1....0....0....1....1....1....1....1....1....1....1....0
..1....1....0....1....0....1....0....1....2....1....1....1....1....0....0....1
..1....0....0....1....1....0....1....0....2....1....0....0....0....0....1....1
..1....0....1....1....0....0....2....1....0....1....0....0....0....0....1....1
..2....0....1....0....1....0....1....1....2....0....0....1....2....1....2....0
CROSSREFS
Column 6 of A210545.
Sequence in context: A023422 A084638 A157021 * A006211 A180209 A344493
KEYWORD
nonn
AUTHOR
R. H. Hardin, formula proved by R. J. Mathar in the Sequence Fans Mailing List, Mar 22 2012
STATUS
approved

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Last modified September 20 10:25 EDT 2024. Contains 376068 sequences. (Running on oeis4.)