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 A178397 Partial sums of round(7^n/10). 1
 0, 1, 6, 40, 280, 1961, 13726, 96080, 672560, 4707921, 32955446, 230688120, 1614816840, 11303717881, 79126025166, 553882176160, 3877175233120, 27140226631841, 189981586422886, 1329871104960200, 9309097734721400 (list; graph; refs; listen; history; text; internal format)
 OFFSET 0,3 LINKS Vincenzo Librandi, Table of n, a(n) for n = 0..400 Mircea Merca, Inequalities and Identities Involving Sums of Integer Functions J. Integer Sequences, Vol. 14 (2011), Article 11.9.1. Index entries for linear recurrences with constant coefficients, signature (8,-8,8,-7). FORMULA a(n) = round((7*7^n-7)/60) = round((7*7^n+5)/60). a(n) = floor((7*7^n+17)/60). a(n) = ceiling((7*7^n-7)/60). a(n) = a(n-4) + 40*7^(n-3), n > 3. a(n) = 8*a(n-1) - 8*a(n-2) + 8*a(n-3) - 7*a(n-4), n > 3. G.f.: -(2*x^2-x)/((x-1)*(7*x-1)*(x^2+1)). EXAMPLE a(4) = 0 + 1 + 5 + 34 + 240 = 280. MAPLE A178397 := proc(n) add( round(7^i/10), i=0..n) ; end proc: MATHEMATICA Accumulate[Floor[7^Range[0, 20]/10+1/2]] (* Harvey P. Dale, Aug 20 2011 *) PROG (MAGMA) [Round((7*7^n-7)/60): n in [0..40]]; // Vincenzo Librandi, Jun 23 2011 (PARI) a(n) = (7*7^n+17)\60; \\ Altug Alkan, Sep 21 2018 CROSSREFS Sequence in context: A081016 A083426 A122471 * A090041 A069720 A005037 Adjacent sequences:  A178394 A178395 A178396 * A178398 A178399 A178400 KEYWORD nonn,less AUTHOR Mircea Merca, Dec 28 2010 STATUS approved

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Last modified October 15 04:33 EDT 2019. Contains 328026 sequences. (Running on oeis4.)