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A154806
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Numbers such that every run length in base 2 is 4.
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2
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15, 240, 3855, 61680, 986895, 15790320, 252645135, 4042322160, 64677154575, 1034834473200, 16557351571215, 264917625139440, 4238682002231055, 67818912035696880, 1085102592571150095, 17361641481138401520
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OFFSET
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1,1
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COMMENTS
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a(n) is the number whose binary representation is A154805(n).
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LINKS
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FORMULA
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Conjecture: a(n) = 1/17*2^(4*n+4) + 15/34*(-1)^(n+1) - 1/2. - Vaclav Kotesovec, Nov 30 2012
Empirical g.f.: 15*x / ((x-1)*(x+1)*(16*x-1)). - Colin Barker, Sep 16 2013
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MATHEMATICA
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LinearRecurrence[{16, 1, -16}, {15, 240, 3855}, 20] (* Harvey P. Dale, Apr 13 2018 *)
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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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EXTENSIONS
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STATUS
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approved
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