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A191296
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Least k such that k-1 and k+1 in binary representation have same number n of 0's as 1's.
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2
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11, 36, 140, 540, 2108, 8316, 33020, 131580, 525308, 2099196, 8392700, 33562620, 134234108, 536903676, 2147549180, 8590065660, 34360000508, 137439477756, 549756862460, 2199025352700, 8796097216508, 35184380477436, 140737505132540, 562949986975740, 2251799880794108, 9007199388958716, 36028797287399420
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OFFSET
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2,1
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LINKS
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FORMULA
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a(0)=11, a(1)=36, a(2)=140, a(3)=540, a(n)=7*a(n-1)-14*a(n-2)+8*a(n-3). - Harvey P. Dale, Jun 10 2011
G.f.: x^2*(11 - 41*x + 42*x^2 - 24*x^3) / ((1 - x)*(1 - 2*x)*(1 - 4*x)). - Colin Barker, Jan 26 2018
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MATHEMATICA
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Join[{11}, LinearRecurrence[{7, -14, 8}, {36, 140, 540}, 40]] (* Harvey P. Dale, Jun 10 2011 *)
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PROG
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(PARI) Vec(x^2*(11 - 41*x + 42*x^2 - 24*x^3) / ((1 - x)*(1 - 2*x)*(1 - 4*x)) + O(x^40)) \\ Colin Barker, Jan 26 2018
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CROSSREFS
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KEYWORD
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nonn,easy,base
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AUTHOR
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EXTENSIONS
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STATUS
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approved
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