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A069895
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2^a(n) divides (2n)^(2n): exponent of 2 in (2n)^(2n).
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7
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2, 8, 6, 24, 10, 24, 14, 64, 18, 40, 22, 72, 26, 56, 30, 160, 34, 72, 38, 120, 42, 88, 46, 192, 50, 104, 54, 168, 58, 120, 62, 384, 66, 136, 70, 216, 74, 152, 78, 320, 82, 168, 86, 264, 90, 184, 94, 480, 98, 200, 102, 312, 106, 216, 110, 448, 114, 232, 118, 360, 122
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OFFSET
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1,1
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LINKS
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FORMULA
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G.f.: Sum_{k>=0} 2^(k+1)*x^2^k/(1-x^2^k)^2. - Ralf Stephan, Jun 07 2003
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MAPLE
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a:= 2*n*padic[ordp](2*n, 2):
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MATHEMATICA
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Table[ Part[ Flatten[ FactorInteger[n^n]], 2], {n, 2, 124, 2}]
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PROG
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(PARI) a(n) = n<<=1; n*valuation(n, 2); \\ Kevin Ryde, Oct 14 2021
(Julia)
function A069895List(length)
a = zeros(Int, length)
for n in 1:length a[n] = 2 * (isodd(n) ? n : n + a[div(n, 2)]) end
a end
(Python)
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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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