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 A195023 a(n) = 14*n^2 - 4*n. 10
 0, 10, 48, 114, 208, 330, 480, 658, 864, 1098, 1360, 1650, 1968, 2314, 2688, 3090, 3520, 3978, 4464, 4978, 5520, 6090, 6688, 7314, 7968, 8650, 9360, 10098, 10864, 11658, 12480, 13330, 14208, 15114, 16048, 17010, 18000, 19018, 20064, 21138, 22240 (list; graph; refs; listen; history; text; internal format)
 OFFSET 0,2 COMMENTS Sequence found by reading the line from 0, in the direction 0, 10, ..., in the Pythagorean spiral whose edges have length A195019 and whose vertices are the numbers A195020. This is the one of the semi-axis of the square spiral, which is related to the primitive Pythagorean triple [3, 4, 5]. LINKS Vincenzo Librandi, Table of n, a(n) for n = 0..10000 Index entries for linear recurrences with constant coefficients, signature (3, -3, 1). FORMULA a(n) = 2*A135703(n). - Bruno Berselli, Oct 13 2011 From Colin Barker, Apr 09 2012: (Start) a(n) = 3*a(n-1) - 3*a(n-2) + a(n-3). G.f.: 2*x*(5+9*x)/(1-x)^3. (End) MATHEMATICA Table[14n^2-4n, {n, 0, 40}] (* or *) LinearRecurrence[{3, -3, 1}, {0, 10, 48}, 50] (* Harvey P. Dale, Sep 05 2012 *) PROG (MAGMA) [14*n^2 - 4*n: n in [0..50]]; // Vincenzo Librandi, Oct 14 2011 (PARI) a(n)=14*n^2-4*n \\ Charles R Greathouse IV, Apr 10 2012 CROSSREFS Cf. A144555, A152760, A195019, A195020, A195024, A195320, A185019, A193053, A198017. Sequence in context: A121075 A121073 A210371 * A277229 A163724 A271638 Adjacent sequences:  A195020 A195021 A195022 * A195024 A195025 A195026 KEYWORD nonn,easy AUTHOR Omar E. Pol, Oct 13 2011 EXTENSIONS Corrected by Vincenzo Librandi, Oct 14 2011 STATUS approved

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Last modified July 27 13:36 EDT 2021. Contains 346306 sequences. (Running on oeis4.)