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 A140323 First differences of A140322. 3
 1, 9, 31, 129, 511, 2049, 8191, 32769, 131071, 524289, 2097151, 8388609, 33554431, 134217729, 536870911, 2147483649, 8589934591, 34359738369, 137438953471, 549755813889, 2199023255551, 8796093022209, 35184372088831, 140737488355329, 562949953421311 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,2 LINKS Vincenzo Librandi, Table of n, a(n) for n = 1..1000 Index entries for linear recurrences with constant coefficients, signature (3,4). FORMULA Mix A004171(2*n)-1, A004171(2*n+1)+1. a(n+1)-4*a(n) = period 2: repeat [5, -5]. G.f.: x*(1 + 6*x)/(1 - 3*x - 4*x^2). - Ilya Gutkovskiy, May 11 2016 From Klaus Purath, Aug 03 2020: Start) a(n) = 8*A015521(n-1) + A102900(n-1). a(n) = 30*4^(n-3) + a(n-2), n>2. a(n+2) = 3*a(n+1) + 4*a(n). (End) MATHEMATICA a[n_] := (2*4^n - (-1)^n); Array[a, 25, 0] (* Robert G. Wilson v, Aug 13 2011 *) CROSSREFS Cf. A140322. Sequence in context: A048374 A226274 A184054 * A160653 A189436 A145950 Adjacent sequences: A140320 A140321 A140322 * A140324 A140325 A140326 KEYWORD nonn,easy AUTHOR Paul Curtz, May 26 2008 EXTENSIONS Extended and offset changed from 0 to 1 by Vincenzo Librandi, Aug 09 2011 STATUS approved

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Last modified February 29 14:40 EST 2024. Contains 370425 sequences. (Running on oeis4.)