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A200984 Number of nX2 0..4 arrays with every row and column nondecreasing rightwards and downwards, and the number of instances of each value within one of each other 1
10, 10, 20, 79, 21, 226, 157, 227, 678, 120, 1272, 789, 1015, 2697, 404, 4232, 2484, 3008, 7496, 1025, 10650, 6050, 7060, 16895, 2181, 22530, 12525, 14255, 33174, 4116, 42336, 23177, 25907, 59073, 7120, 72992, 39504, 43560, 97792, 11529, 117882, 63234 (list; graph; refs; listen; history; text; internal format)
OFFSET
1,1
COMMENTS
Column 2 of A200990
LINKS
FORMULA
Empirical: a(n) = 5*a(n-5) -10*a(n-10) +10*a(n-15) -5*a(n-20) +a(n-25)
Subsequences for n modulo 5 = 1,2,3,4,0:
p=(n+4)/5: a(n) = (115/6)*p^4 - 11*p^3 + (11/6)*p^2
q=(n+3)/5: a(n) = (115/12)*q^4 + (1/2)*q^3 - (1/12)*q^2
r=(n+2)/5: a(n) = (115/12)*r^4 + (49/6)*r^3 + (23/12)*r^2 + (1/3)*r
s=(n+1)/5: a(n) = (115/6)*s^4 + 35*s^3 + (125/6)*s^2 + 4*s
t=(n+0)/5: a(n) = (23/12)*t^4 + (37/6)*t^3 + (91/12)*t^2 + (13/3)*t + 1
EXAMPLE
Some solutions for n=3
..0..1....0..2....0..1....0..3....0..2....0..1....0..1....0..2....0..2....0..2
..1..2....1..3....2..3....1..3....1..3....0..3....0..2....1..3....0..3....1..3
..3..4....4..4....2..4....2..4....2..4....2..4....3..4....3..4....1..4....1..4
CROSSREFS
Sequence in context: A076817 A324494 A344104 * A361037 A299576 A185993
KEYWORD
nonn
AUTHOR
R. H. Hardin Nov 25 2011
STATUS
approved

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Last modified July 13 07:46 EDT 2024. Contains 374274 sequences. (Running on oeis4.)