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A204644 Number of (n+1) X 2 0..1 arrays with column and row pair sums b(i,j)=a(i,j)+a(i,j-1) and c(i,j)=a(i,j)+a(i-1,j) nondecreasing in column and row directions, respectively. 2
8, 16, 28, 48, 80, 132, 216, 352, 572, 928, 1504, 2436, 3944, 6384, 10332, 16720, 27056, 43780, 70840, 114624, 185468, 300096, 485568, 785668, 1271240, 2056912, 3328156, 5385072, 8713232, 14098308, 22811544, 36909856, 59721404, 96631264, 156352672, 252983940 (list; graph; refs; listen; history; text; internal format)
OFFSET
1,1
LINKS
FORMULA
Empirical: a(n) = 2*a(n-1) - a(n-3).
From the empirical recurrence, a(n) = 4*(Fibonacci(n + 3) - 1). - Ehren Metcalfe, Apr 04 2019
EXAMPLE
Some solutions for n=5:
0 1 0 1 0 0 0 0 0 1 0 0 1 0 0 0 0 0 0 0
0 1 0 1 0 0 0 0 1 0 0 1 0 1 0 0 0 0 1 1
1 0 0 1 0 0 0 0 0 1 0 1 1 0 0 1 0 0 1 1
0 1 0 1 0 1 0 0 1 1 0 1 0 1 0 1 0 1 1 1
0 1 1 0 1 0 0 0 1 1 0 1 1 0 0 1 1 1 1 1
1 1 0 1 0 1 0 1 1 1 0 1 0 1 1 1 1 1 1 1
CROSSREFS
Column 1 of A204651.
Sequence in context: A045237 A255993 A299644 * A191271 A047925 A332918
KEYWORD
nonn
AUTHOR
R. H. Hardin, Jan 17 2012
STATUS
approved

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Last modified June 20 08:07 EDT 2024. Contains 373512 sequences. (Running on oeis4.)