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 A140689 a(n) = n*(3*n + 20). 7
 0, 23, 52, 87, 128, 175, 228, 287, 352, 423, 500, 583, 672, 767, 868, 975, 1088, 1207, 1332, 1463, 1600, 1743, 1892, 2047, 2208, 2375, 2548, 2727, 2912, 3103, 3300, 3503, 3712, 3927, 4148, 4375, 4608, 4847, 5092, 5343, 5600, 5863 (list; graph; refs; listen; history; text; internal format)
 OFFSET 0,2 LINKS Harvey P. Dale, Table of n, a(n) for n = 0..1000 Index entries for linear recurrences with constant coefficients, signature (3,-3,1). FORMULA a(n) = 3*n^2 + 20*n. a(n) = a(n-1) + 6*n + 17 (with a(0)=0). - Vincenzo Librandi, Dec 15 2010 a(n) = 3*a(n-1)-3*a(n-2)+a(n-3), with a(0)=0, a(1)=23, a(2)=52. - Harvey P. Dale, Apr 29 2016 From G. C. Greubel, Jul 21 2017: (Start) G.f.: x*(23 - 17*x)/(1 - x)^3. E.g.f.: x*(3*x + 23)*exp(x). (End) MATHEMATICA a[n_]:=Sum[6*i+17, {i, 1, n}]; (* Vladimir Joseph Stephan Orlovsky, Dec 04 2008 *) Table[n(3n+20), {n, 0, 50}] (* or *) LinearRecurrence[{3, -3, 1}, {0, 23, 52}, 50] (* Harvey P. Dale, Apr 29 2016 *) PROG (PARI) a(n)=n*(3*n+20) \\ Charles R Greathouse IV, Jun 17 2017 CROSSREFS Cf. A033428, A045944, A140676, A067725, A140677, A140678, A067707, A140679, A140680, A140681. Sequence in context: A281266 A165432 A067625 * A172034 A335655 A113912 Adjacent sequences:  A140686 A140687 A140688 * A140690 A140691 A140692 KEYWORD easy,nonn AUTHOR Omar E. Pol, May 22 2008 STATUS approved

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Last modified November 30 19:02 EST 2021. Contains 349424 sequences. (Running on oeis4.)