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A345176
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a(n) = Sum_{k=1..n} floor(n/k)^k.
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3
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1, 3, 5, 10, 12, 26, 28, 52, 73, 115, 117, 295, 297, 439, 713, 1160, 1162, 2448, 2450, 4644, 6832, 8902, 8904, 23536, 25639, 33857, 53247, 84961, 84963, 192237, 192239, 318477, 493909, 625015, 695789, 1761668, 1761670, 2285996, 3872598, 6255230, 6255232, 13392362
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OFFSET
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1,2
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LINKS
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FORMULA
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G.f.: (1/(1 - x)) * Sum_{j>=1} Sum_{k>=1} (k*x^k)^j * (1 - x^j).
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MATHEMATICA
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a[n_] := Sum[Floor[n/k]^k, {k, 1, n}]; Array[a, 40] (* Amiram Eldar, Jun 10 2021 *)
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PROG
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(PARI) a(n) = sum(k=1, n, (n\k)^k);
(PARI) my(N=66, x='x+O('x^N)); Vec(sum(j=1, N, (1-x^j)*sum(k=1, N, (k*x^k)^j))/(1-x))
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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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