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A250728 Number of (n+1)X(7+1) 0..1 arrays with nondecreasing x(i,j)+x(i,j-1) in the i direction and nondecreasing min(x(i,j),x(i-1,j)) in the j direction 1
1302, 3173, 6257, 11377, 19887, 34069, 57397, 95231, 155263, 248537, 390263, 601256, 909242, 1350837, 1973466, 2838027, 4021571, 5620807, 7755707, 10574024, 14256002, 19020095, 25128978, 32896671, 42696063, 54967661, 70228855, 89084528 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

Column 7 of A250729

LINKS

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

FORMULA

Empirical: a(n) = 8*a(n-1) -27*a(n-2) +48*a(n-3) -42*a(n-4) +42*a(n-6) -48*a(n-7) +27*a(n-8) -8*a(n-9) +a(n-10) for n>17

Empirical for n mod 2 = 0: a(n) = (1/20160)*n^8 + (1/420)*n^7 + (71/1440)*n^6 + (71/120)*n^5 + (17767/2880)*n^4 + (1159/120)*n^3 + (533033/1680)*n^2 + (86336/105)*n - 5 for n>7

Empirical for n mod 2 = 1: a(n) = (1/20160)*n^8 + (1/420)*n^7 + (71/1440)*n^6 + (71/120)*n^5 + (17767/2880)*n^4 + (1159/120)*n^3 + (533033/1680)*n^2 + (86336/105)*n - 17 for n>7

EXAMPLE

Some solutions for n=4

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

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

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

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

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

CROSSREFS

Sequence in context: A022057 A107521 A226144 * A071847 A014356 A252308

Adjacent sequences:  A250725 A250726 A250727 * A250729 A250730 A250731

KEYWORD

nonn

AUTHOR

R. H. Hardin, Nov 27 2014

STATUS

approved

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Last modified September 19 15:08 EDT 2019. Contains 327198 sequences. (Running on oeis4.)