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 A060188 A column and diagonal of A060187. 8
 1, 6, 23, 76, 237, 722, 2179, 6552, 19673, 59038, 177135, 531428, 1594309, 4782954, 14348891, 43046704, 129140145, 387420470, 1162261447, 3486784380, 10460353181, 31381059586, 94143178803, 282429536456, 847288609417 (list; graph; refs; listen; history; text; internal format)
 OFFSET 2,2 COMMENTS Sums of rows of the numerators and of the denominators of the redundant Stern-Brocot structure A152975/A152976: a(n+2) = Sum_{k=2^n..(2^(n+1) -1)} A152975(k) = Sum_{k=2^n..(2^(n+1) -1)} A152976(k). - Reinhard Zumkeller, Dec 22 2008 LINKS Vincenzo Librandi, Table of n, a(n) for n = 2..2000 P. A. MacMahon, The divisors of numbers, Proc. London Math. Soc., (2) 19 (1920), 305-340; Coll. Papers II, pp. 267-302. Index entries for linear recurrences with constant coefficients, signature (5,-7,3). FORMULA a(n) = 3^(n-1) - n = A061980(n-1, 2). - Henry Bottomley, May 24 2001 From Paul Barry, Jun 24 2003: (Start) With offset 0, this is 3^(n+1) - n - 2. Partial sums of A048473. (End) From Colin Barker, Dec 19 2012: (Start) a(n) = 5*a(n-1) - 7*a(n-2) + 3*a(n-3). G.f.: x^2*(1 + x)/((1-x)^2*(1-3*x)). (End) E.g.f.: (exp(3*x) - 3*x*exp(x) - 1)/3. - Wolfdieter Lang, Apr 17 2017 MAPLE a[0]:=1:for n from 1 to 24 do a[n]:=(4*a[n-1]-3*a[n-2]+2) od: seq(a[n], n=0..24); # Zerinvary Lajos, Jun 08 2007 MATHEMATICA Table[3^(n-1) -n, {n, 2, 30}] (* Vladimir Joseph Stephan Orlovsky, Nov 15 2008 *) PROG (Magma) [3^(n-1)-n: n in [2..30]]; // Vincenzo Librandi, Sep 05 2011 (Sage) [3^(n-1) -n for n in (2..32)] # G. C. Greubel, Jan 07 2022 CROSSREFS Cf. A048473, A060187 (first differences). Sequence in context: A136530 A259033 A054459 * A058751 A034359 A220148 Adjacent sequences: A060185 A060186 A060187 * A060189 A060190 A060191 KEYWORD nonn,easy AUTHOR N. J. A. Sloane, Mar 20 2001 EXTENSIONS More terms from Vladeta Jovovic, Mar 20 2001 STATUS approved

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Last modified October 3 10:22 EDT 2023. Contains 365859 sequences. (Running on oeis4.)