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A293525
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Square array A(n,k), n >= 0, k >= 1, read by antidiagonals, where column k is the expansion of e.g.f. Product_{j > 0, j mod k > 0} exp(x^j).
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2
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1, 1, 0, 1, 1, 0, 1, 1, 1, 0, 1, 1, 3, 7, 0, 1, 1, 3, 7, 25, 0, 1, 1, 3, 13, 49, 181, 0, 1, 1, 3, 13, 49, 321, 1201, 0, 1, 1, 3, 13, 73, 381, 2131, 10291, 0, 1, 1, 3, 13, 73, 381, 2971, 19783, 97777, 0, 1, 1, 3, 13, 73, 501, 3331, 26713, 195777, 1013545, 0, 1, 1
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OFFSET
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0,13
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LINKS
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FORMULA
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E.g.f. of column k: exp((Sum_{j=1..k-1} x^j)/(1 - x^k)).
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EXAMPLE
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Square array begins:
1, 1, 1, 1, 1, ...
0, 1, 1, 1, 1, ...
0, 1, 3, 3, 3, ...
0, 7, 7, 13, 13, ...
0, 25, 49, 49, 73, ...
0, 181, 321, 381, 381, ...
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MATHEMATICA
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kmax = 12; col[k_] := PadRight[(Exp[Sum[x^j, {j, 1, k - 1}]/(1 - x^k)] + O[x]^kmax // CoefficientList[#, x] &), kmax]*Range[0, kmax - 1]!; A = Array[col, kmax]; Table[A[[n - k + 1, k]], {n, 1, kmax}, {k, 1, n}] // Flatten (* Jean-François Alcover, Oct 12 2017, from formula *)
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CROSSREFS
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KEYWORD
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AUTHOR
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STATUS
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approved
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