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 A191296 Least k such that k-1 and k+1 in binary representation have same number n of 0's as 1's. 2
 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 (list; graph; refs; listen; history; text; internal format)
 OFFSET 2,1 LINKS Colin Barker, Table of n, a(n) for n = 2..1000 Index entries for linear recurrences with constant coefficients, signature (7,-14,8). FORMULA a(n) = 2*(2^(n-1) + 2)*(2^(n-1) - 1) for n>=3. - Nathaniel Johnston, May 30 2011 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 MATHEMATICA Join[{11}, LinearRecurrence[{7, -14, 8}, {36, 140, 540}, 40]] (* Harvey P. Dale, Jun 10 2011 *) PROG (PARI) a(n)=if(n<3, 11, 2*(2^(n-1) + 2)*(2^(n-1) - 1)) \\ Charles R Greathouse IV, Jun 01 2011 (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 CROSSREFS Cf. A031443 (digitally balanced numbers), A191292, A191341. Sequence in context: A005000 A006505 A004637 * A052526 A306498 A195201 Adjacent sequences: A191293 A191294 A191295 * A191297 A191298 A191299 KEYWORD nonn,easy,base AUTHOR Juri-Stepan Gerasimov, May 29 2011 EXTENSIONS a(11)-a(27) and recurrence from Charles R Greathouse IV, May 29 2011 STATUS approved

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Last modified September 21 19:32 EDT 2023. Contains 365503 sequences. (Running on oeis4.)