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A210544 Number of arrays of n nonnegative integers with value i>0 appearing only after i-1 has appeared at least 7 times 1
1, 1, 1, 1, 1, 1, 1, 2, 4, 8, 16, 32, 64, 128, 257, 524, 1106, 2470, 5924, 15262, 41690, 118595, 345861, 1023028, 3050590, 9146312, 27567958, 83678750, 256632743, 798853376, 2537255097, 8264988956, 27723246374, 95941707086, 342355797248 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,8

COMMENTS

Column 7 of A210545

LINKS

R. H. Hardin, Table of n, a(n) for n = 1..210

FORMULA

a(n) = 1 if n<=7 else sum{i=0..n-7}(binomial(n-7,i)*a(i))

EXAMPLE

Some solutions for n=19

..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....0....0....0....0....0....0....0....0....0....0....0....0....0....0....0

..0....1....1....0....1....1....0....1....1....1....1....0....1....0....0....0

..1....1....0....0....0....1....1....0....0....1....1....1....0....1....1....1

..1....0....1....1....1....0....1....0....0....1....0....0....0....1....0....1

..0....1....0....0....0....1....1....0....1....1....1....1....0....1....1....1

..0....0....1....0....1....0....1....0....1....0....1....0....0....1....1....0

..1....0....0....1....1....1....0....0....0....1....1....0....1....1....1....0

..0....1....1....0....1....1....0....0....0....1....1....1....0....1....1....0

..0....1....1....0....1....1....0....0....1....0....1....0....0....1....1....1

..1....1....1....1....0....1....0....0....1....1....2....1....1....0....1....0

..1....1....1....1....0....2....0....0....0....1....1....1....1....0....2....1

..0....0....1....1....1....1....0....0....1....0....1....1....0....1....2....1

..0....1....1....1....0....2....1....1....1....0....0....0....1....1....2....1

CROSSREFS

Sequence in context: A275063 A186026 A023423 * A180210 A274861 A290666

Adjacent sequences:  A210541 A210542 A210543 * A210545 A210546 A210547

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 February 24 12:46 EST 2018. Contains 299623 sequences. (Running on oeis4.)