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 A152994 Nine times hexagonal numbers: a(n) = 9*n*(2*n-1). 3
 0, 9, 54, 135, 252, 405, 594, 819, 1080, 1377, 1710, 2079, 2484, 2925, 3402, 3915, 4464, 5049, 5670, 6327, 7020, 7749, 8514, 9315, 10152, 11025, 11934, 12879, 13860, 14877, 15930, 17019, 18144, 19305, 20502, 21735, 23004, 24309 (list; graph; refs; listen; history; text; internal format)
 OFFSET 0,2 COMMENTS Sequence found by reading the line from 0, in the direction 0, 9,..., in the square spiral whose vertices are the generalized hendecagonal numbers A195160. - Omar E. Pol, Sep 18 2011 LINKS Ivan Panchenko, Table of n, a(n) for n = 0..1000 Index entries for linear recurrences with constant coefficients, signature (3,-3,1). FORMULA a(n) = 18*n^2 - 9*n = A000384(n)*9 = A094159(n)*3. a(n) = a(n-1) + 36*n - 27 for n>0, a(0)=0. - Vincenzo Librandi, Dec 15 2010 a(n) = Sum_{i = 2..10} P(i,n), where P(i,m) = m*((i-2)*m-(i-4))/2. - Bruno Berselli, Jul 04 2018 From G. C. Greubel, Sep 01 2019: (Start) G.f.: 9*x*(1+3*x)/(1-x)^3. E.g.f.: 9*x*(1+2*x)*exp(x). (End) MAPLE seq(9*n*(2*n-1), n=0..40); # G. C. Greubel, Sep 01 2019 MATHEMATICA Table[9*n*(2*n-1), {n, 0, 40}] (* G. C. Greubel, Sep 01 2019 *) PROG (PARI) a(n)=9*n*(2*n-1) \\ Charles R Greathouse IV, Jun 17 2017 (MAGMA) [9*n*(2*n-1): n in [0..40]]; // G. C. Greubel, Sep 01 2019 (Sage) [9*n*(2*n-1) for n in (0..40)] # G. C. Greubel, Sep 01 2019 (GAP) List([0..40], n-> 9*n*(2*n-1)); # G. C. Greubel, Sep 01 2019 CROSSREFS Cf. A000384, A094159. Similar sequences are listed in A316466. Sequence in context: A224484 A225791 A093846 * A034719 A013567 A073974 Adjacent sequences:  A152991 A152992 A152993 * A152995 A152996 A152997 KEYWORD nonn,easy AUTHOR Omar E. Pol, Dec 22 2008 STATUS approved

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Last modified September 20 16:30 EDT 2019. Contains 327242 sequences. (Running on oeis4.)