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A357901
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a(n) = Sum_{k=0..floor(n/3)} |Stirling1(n - 2*k,k)|.
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4
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1, 0, 0, 1, 1, 2, 7, 27, 131, 771, 5320, 42119, 376174, 3740018, 40956593, 489749100, 6348744124, 88677555115, 1327628770657, 21208195526882, 360053293342379, 6473501562355779, 122874692176838047, 2455382300127368557, 51524333987938459606, 1132787775301639812263
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history;
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internal format)
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OFFSET
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0,6
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LINKS
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FORMULA
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G.f.: Sum_{k>=0} x^k * Product_{j=0..k-1} (j + x^2).
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PROG
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(PARI) a(n) = sum(k=0, n\3, abs(stirling(n-2*k, k, 1)));
(PARI) my(N=30, x='x+O('x^N)); Vec(sum(k=0, N, x^k*prod(j=0, k-1, j+x^2)))
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CROSSREFS
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KEYWORD
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nonn
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AUTHOR
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STATUS
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approved
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