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A204647 Number of (n+1) X 5 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. 1
48, 90, 178, 330, 571, 938, 1478, 2248, 3317, 4766, 6690, 9198, 12415, 16482, 21558, 27820, 35465, 44710, 55794, 68978, 84547, 102810, 124102, 148784, 177245, 209902, 247202, 289622, 337671, 391890, 452854, 521172, 597489, 682486, 776882, 881434 (list; graph; refs; listen; history; text; internal format)
OFFSET
1,1
COMMENTS
Column 4 of A204651.
LINKS
FORMULA
Empirical: a(n) = 5*a(n-1) -9*a(n-2) +5*a(n-3) +5*a(n-4) -9*a(n-5) +5*a(n-6) -a(n-7) for n>9.
Conjectures from Colin Barker, Jun 08 2018: (Start)
G.f.: x*(48 - 150*x + 160*x^2 + 10*x^3 - 167*x^4 + 145*x^5 - 43*x^6 - 5*x^7 + 4*x^8) / ((1 - x)^6*(1 + x)).
a(n) = (1920 + 9776*n + 3480*n^2 + 540*n^3 + 90*n^4 + 4*n^5)/480 for n>2 and even.
a(n) = (1950 + 9776*n + 3480*n^2 + 540*n^3 + 90*n^4 + 4*n^5)/480 for n>2 and odd.
(End)
EXAMPLE
Some solutions for n=5:
..0..0..0..1..1....0..0..0..0..0....0..0..0..0..0....0..0..0..0..0
..0..0..0..1..1....0..0..0..0..0....0..0..0..0..0....0..0..0..0..0
..0..0..1..1..1....0..0..0..0..0....0..0..0..1..1....0..0..0..0..0
..1..1..1..1..1....0..0..0..0..1....0..0..0..1..1....0..0..0..0..1
..1..1..1..1..1....0..0..0..0..1....0..1..1..1..1....0..0..0..1..1
..1..1..1..1..1....0..0..0..1..0....0..1..1..1..1....0..0..1..1..1
CROSSREFS
Cf. A204651.
Sequence in context: A260099 A224546 A247720 * A260980 A260070 A260973
KEYWORD
nonn
AUTHOR
R. H. Hardin, Jan 17 2012
STATUS
approved

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Last modified June 20 03:21 EDT 2024. Contains 373512 sequences. (Running on oeis4.)