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A136494
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Number of permutation symmetries in the binary expansion of n.
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1
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1, 1, 1, 2, 2, 2, 2, 6, 6, 4, 4, 6, 4, 6, 6, 24, 24, 12, 12, 12, 12, 12, 12, 24, 12, 12, 12, 24, 12, 24, 24, 120, 120, 48, 48, 36, 48, 36, 36, 48, 48, 36, 36, 48, 36, 48, 48, 120, 48, 36, 36, 48, 36, 48, 48, 120, 36, 48, 48, 120, 48, 120, 120, 720, 720
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OFFSET
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0,4
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LINKS
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FORMULA
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EXAMPLE
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a(14) = 6 because there are 3! permutation symmetries of 1's * the 0! permutation symmetries of 0's.
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MATHEMATICA
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a[n_] := Times @@ (DigitCount[n, 2]!); Array[a, 65, 0] (* Amiram Eldar, Jul 29 2023 *)
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PROG
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(PARI) a(n) = {if(n==0, 1, my(w=hammingweight(n)); w!*(1+logint(n, 2)-w)!)} \\ Andrew Howroyd, Jan 12 2020
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CROSSREFS
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KEYWORD
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base,nonn
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AUTHOR
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EXTENSIONS
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STATUS
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approved
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