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A122248
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a(n) - a(n-1) = A113474(n).
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11
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0, 1, 3, 5, 9, 13, 18, 23, 31, 39, 48, 57, 68, 79, 91, 103, 119, 135, 152, 169, 188, 207, 227, 247, 270, 293, 317, 341, 367, 393, 420, 447, 479, 511, 544, 577, 612, 647, 683, 719, 758, 797, 837, 877, 919, 961, 1004, 1047, 1094, 1141, 1189
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OFFSET
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0,3
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COMMENTS
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LINKS
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FORMULA
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G.f.: (1/(1-x))*Sum{k=0..infinity, x^(2^k)/((1-x)*(1-x^(2^k)))}-x^2/(1-x)^3.
a(n) = Sum_{k=1..n} Sum_{j=0..n} floor(k/2^j) - binomial(n,2).
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PROG
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(PARI) a(n) = sum(k=1, n, sum(j=0, n, k\2^j)) - binomial(n, 2); \\ Michel Marcus, Mar 09 2023
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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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