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Search: id:A144000
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| A144000 |
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Rectangular array by antidiagonals: label each unit square in the 1st quadrant lattice by its northeast vertex (x,y) and mark squares for which x+y=0(mod 3); then R(m,n) is the number of marked squares in the rectangle [0,m]x[0,n]. |
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+0
6
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| 1, 1, 1, 2, 2, 2, 3, 4, 4, 3, 3, 5, 6, 5, 3, 4, 6, 8, 8, 6, 4, 5, 8, 10, 11, 10, 8, 5, 5, 9, 12, 13, 13, 12, 9, 5, 6, 10, 14, 16, 16, 16, 14, 10, 6, 7, 12, 16, 19, 20, 20, 19, 16, 12, 7, 7, 13, 18, 21, 23, 24, 23, 21, 18, 13, 7, 8, 14, 20, 24, 26, 28, 28, 26, 24, 20, 14, 8, 9, 16, 22, 27, 30
(list; table; graph; listen)
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OFFSET
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1,4
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COMMENT
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Row 3n is given by 2n*(1,2,3,4,5,6,...).
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FORMULA
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R(m,n)=Floor((2mn+1)/3) if n=1(mod 3) and Floor(2mn/3) otherwise.
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CROSSREFS
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Cf. A143996, A143997, A143998, A144399, A144001.
Sequence in context: A027300 A085313 A065458 this_sequence A085202 A096009 A000224
Adjacent sequences: A143997 A143998 A143999 this_sequence A144001 A144002 A144003
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KEYWORD
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nonn,tabl
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AUTHOR
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Clark Kimberling (ck6(AT)evansville.edu), Sep 07 2008
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