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A099241
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Sums of antidiagonals of A099239.
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2
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1, 2, 4, 9, 22, 57, 155, 441, 1311, 4066, 13130, 44046, 153144, 550706, 2044248, 7819897, 30779570, 124487688, 516723174, 2198726181, 9581247648, 42717268934, 194688593966, 906331074605, 4306472500778, 20871165469241, 103106015116437
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OFFSET
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0,2
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LINKS
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FORMULA
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a(n) = Sum_{k=0..n} Sum_{j=0..n-k} binomial(k*(n-k) - (k-1)*(j-1), j).
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MATHEMATICA
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A099239[n_, k_]:= Sum[Binomial[k*(n-k) -(k-1)*(j-1), j], {j, 0, n-k}];
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PROG
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(Sage)
def A099239(n, k): return sum(binomial(k*(n-k)-(k-1)*(j-1), j) for j in (0..n-k))
(Magma)
A099239:= func< n, k | (&+[Binomial(k*(n-k) -(k-1)*(j-1), j): j in [0..n-k]]) >;
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CROSSREFS
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KEYWORD
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easy,nonn
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AUTHOR
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STATUS
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approved
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