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A255743
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a(1) = 1; for n > 1, a(n) = 9*8^{A000120(n-1)-1}.
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5
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1, 9, 9, 72, 9, 72, 72, 576, 9, 72, 72, 576, 72, 576, 576, 4608, 9, 72, 72, 576, 72, 576, 576, 4608, 72, 576, 576, 4608, 576, 4608, 4608, 36864, 9, 72, 72, 576, 72, 576, 576, 4608, 72, 576, 576, 4608, 576, 4608, 4608, 36864, 72, 576, 576, 4608, 576, 4608, 4608
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OFFSET
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1,2
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COMMENTS
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Also, this is a row of the square array A255740.
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LINKS
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EXAMPLE
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Written as an irregular triangle in which the row lengths are the terms of A011782, the sequence begins:
1;
9;
9, 72;
9, 72, 72, 576;
9, 72, 72, 576, 72, 576, 576, 4608;
...
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MATHEMATICA
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MapAt[Floor, Array[9*8^(DigitCount[# - 1, 2, 1] - 1) &, 55], 1] (* Michael De Vlieger, Nov 03 2022 *)
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PROG
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(PARI) a(n) = if (n==1, 1, 9*8^(hammingweight(n-1)-1)); \\ Michel Marcus, Mar 15 2015
(Python 3.10+)
def A255743(n): return 1 if n == 1 else 9*(1<<((n-1).bit_count()-1)*3) # Chai Wah Wu, Nov 15 2022
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CROSSREFS
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Cf. A000120, A151787, A147582, A151789, A151779, A151791, A151782, A255740, A255741, A255744, A255745, A255764.
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KEYWORD
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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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