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A049581
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Table T(n,k) = |n-k| read by antidiagonals (n >= 0, k >= 0).
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7
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0, 1, 1, 2, 0, 2, 3, 1, 1, 3, 4, 2, 0, 2, 4, 5, 3, 1, 1, 3, 5, 6, 4, 2, 0, 2, 4, 6, 7, 5, 3, 1, 1, 3, 5, 7, 8, 6, 4, 2, 0, 2, 4, 6, 8, 9, 7, 5, 3, 1, 1, 3, 5, 7, 9, 10, 8, 6, 4, 2, 0, 2, 4, 6, 8, 10, 11, 9, 7, 5, 3, 1, 1, 3, 5, 7, 9, 11, 12, 10, 8, 6, 4, 2, 0, 2, 4, 6, 8, 10, 12
(list; table; graph; refs; listen; history; internal format)
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OFFSET
| 0,4
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COMMENTS
| Commutative non-associative operator with identity 0. T(nx,kx) = x T(n,k). A multiplicative analogue is A089913. - Marc LeBrun (mlb(AT)well.com), Nov 14 2003
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FORMULA
| G.f. (x + y - 4xy + x^2y + xy^2)/((1-x)^2 (1-y)^2) (1-xy)) = (x/(1-x)^2 + y/(1-y)^2)/(1-xy). T(n,0)=T(0,n)=n; T(n+1,k+1)=T(n,k). - Frank Adams-Watters (FrankTAW(AT)Netscape.net), Feb 06 2006
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EXAMPLE
| 0; 1 1; 2 0 2; 3 1 1 3; 4 2 0 2 4; ...
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CROSSREFS
| Cf. A003989, A003990, A003991, A003056, A004247.
Cf. A089913. Apart from signs, same as A114327.
Sequence in context: A105805 A194547 * A114327 A073450 A071447 A063514
Adjacent sequences: A049578 A049579 A049580 * A049582 A049583 A049584
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KEYWORD
| nonn,tabl,easy,nice
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AUTHOR
| N. J. A. Sloane (njas(AT)research.att.com).
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