The OEIS is supported by the many generous donors to the OEIS Foundation.

 Hints (Greetings from The On-Line Encyclopedia of Integer Sequences!)
 A129371 a(n) = Sum_{k=0..floor(n/2)} (n-k)^2. 2
 0, 1, 5, 13, 29, 50, 86, 126, 190, 255, 355, 451, 595, 728, 924, 1100, 1356, 1581, 1905, 2185, 2585, 2926, 3410, 3818, 4394, 4875, 5551, 6111, 6895, 7540, 8440, 9176, 10200, 11033, 12189, 13125, 14421, 15466, 16910, 18070 (list; graph; refs; listen; history; text; internal format)
 OFFSET 0,3 COMMENTS Partial sums of A129370. LINKS Table of n, a(n) for n=0..39. Index entries for linear recurrences with constant coefficients, signature (1,3,-3,-3,3,1,-1). [From R. J. Mathar, Apr 21 2010] FORMULA G.f.: x*(1+4*x+5*x^2+4*x^3)/((1-x)*(1-x^2)^3). a(n) = Sum_{k = floor((n+1)/2)..n} k^2. From R. J. Mathar, Apr 21 2010: (Start) a(n) = a(n-1) +3*a(n-2) -3*a(n-3) -3*a(n-4) +3*a(n-5) +a(n-6) -a(n-7). a(n) = 7*n^3/24+9*n^2/16+7*n/48+n*(-1)^n*(n-1)/16. (End) MATHEMATICA Accumulate[Table[n^2-(n-1)^2 (1-(-1)^n)/8, {n, 0, 50}]] (* Harvey P. Dale, Oct 22 2011 *) CROSSREFS Cf. A129370. Sequence in context: A272750 A272801 A100438 * A212008 A194270 A194700 Adjacent sequences: A129368 A129369 A129370 * A129372 A129373 A129374 KEYWORD easy,nonn AUTHOR Paul Barry, Apr 11 2007 STATUS approved

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

Last modified October 3 05:49 EDT 2023. Contains 365842 sequences. (Running on oeis4.)