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A108019
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a(n) = (8^n - 1)*4/7.
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4
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0, 4, 36, 292, 2340, 18724, 149796, 1198372, 9586980, 76695844, 613566756, 4908534052, 39268272420, 314146179364, 2513169434916, 20105355479332, 160842843834660, 1286742750677284, 10293942005418276, 82351536043346212
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OFFSET
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0,2
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COMMENTS
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Numbers n whose binary representation is 100, n times.
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LINKS
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FORMULA
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a(n) = 9*a(n-1) - 8*a(n-2).
G.f.: 4*x/((x-1)*(8*x-1)). (End)
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EXAMPLE
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a(3)=292 because 292 translated in base 2 is three times 100: 100100100.
Octal............Decimal
0......................0
4......................4
44....................36
444..................292
4444................2340
44444..............18724
444444............149796
4444444..........1198372
44444444.........9586980
444444444.......76695844
4444444444.....613566756,
etc. (End)
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MATHEMATICA
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Table[ FromDigits[ Flatten[ Table[{1, 0, 0}, {i, n}]], 2], {n, 0, 19}] (* Robert G. Wilson v, Jun 01 2005 *)
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PROG
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CROSSREFS
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KEYWORD
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nonn,easy
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AUTHOR
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EXTENSIONS
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STATUS
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approved
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