This site is supported by donations to The OEIS Foundation. Hints (Greetings from The On-Line Encyclopedia of Integer Sequences!)
 A118015 a(n) = floor(n^2/5). 15
 0, 0, 0, 1, 3, 5, 7, 9, 12, 16, 20, 24, 28, 33, 39, 45, 51, 57, 64, 72, 80, 88, 96, 105, 115, 125, 135, 145, 156, 168, 180, 192, 204, 217, 231, 245, 259, 273, 288, 304, 320, 336, 352, 369, 387, 405, 423, 441, 460, 480, 500, 520, 540, 561, 583, 605, 627, 649, 672 (list; graph; refs; listen; history; text; internal format)
 OFFSET 0,5 COMMENTS It seems that for n>=5, a(n) = maximum number of non-overlapping 1x5 rectangles that can be packed into an n x n square. Rectangles can only be placed parallel to the sides of the square. Verified with Lobato's program. - Dmitry Kamenetsky, Aug 03 2009 LINKS Vincenzo Librandi, Table of n, a(n) for n = 0..5000 Index entries for linear recurrences with constant coefficients, signature (2,-1,0,0,1,-2,1). FORMULA G.f.: x^3*(1 + x)/((1 + x + x^2 + x^3 + x^4)*(1 - x)^3). - Klaus Brockhaus, Nov 18 2008 a(n) = A008732(n-4) + A008732(n-3). - R. J. Mathar, Nov 22 2008 a(5*m+r) = m*(5*m + 2*r) + a(r), with m >= 0 and 0 <= r < 5. Example: for m=4 and r=3, a(5*4+3) = a(23) = 4*(5*4 + 2*3) + a(3) = 104 + 1 = 105. - Bruno Berselli, Dec 12 2016 MATHEMATICA Table[Floor[n^2/5], {n, 0, 60}] (* Bruno Berselli, Dec 12 2016 *) PROG (MAGMA) [ n^2 div 5: n in [0..58] ]; // Klaus Brockhaus, Nov 18 2008 (PARI) a(n)=n^2\5 \\ Charles R Greathouse IV, Sep 24 2015 (Python) [int(n**2/5) for n in xrange(60)] # Bruno Berselli, Dec 12 2016 (Sage) [floor(n^2/5) for n in xrange(60)] # Bruno Berselli, Dec 12 2016 CROSSREFS Cf. A000212, A000290, A007590, A002620, A056827, A118013, A279169. Sequence in context: A226332 A226331 A316312 * A265057 A122643 A194240 Adjacent sequences:  A118012 A118013 A118014 * A118016 A118017 A118018 KEYWORD nonn,easy AUTHOR Reinhard Zumkeller, Apr 10 2006 EXTENSIONS Edited by Charles R Greathouse IV, Apr 20 2010 STATUS approved

Lookup | Welcome | Wiki | Register | Music | Plot 2 | Demos | Index | Browse | More | WebCam
Contribute new seq. or comment | Format | Style Sheet | Transforms | Superseeker | Recent
The OEIS Community | Maintained by The OEIS Foundation Inc.

Last modified August 21 18:58 EDT 2019. Contains 326168 sequences. (Running on oeis4.)