The OEIS Foundation is supported by donations from users of the OEIS and by a grant from the Simons Foundation.

 Hints (Greetings from The On-Line Encyclopedia of Integer Sequences!)
 A196875 a(n) = a(n-4) + a(n-3) + a(n-2) + a(n-1) + (n-5). 1
 1, 1, 1, 1, 4, 8, 16, 32, 64, 125, 243, 471, 911, 1759, 3394, 6546, 12622, 24334, 46910, 90427, 174309, 335997, 647661, 1248413, 2406400, 4638492, 8940988, 17234316, 33220220, 64034041, 123429591, 237918195, 458602075, 883983931, 1703933822, 3284438054 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,5 LINKS Alois P. Heinz, Table of n, a(n) for n = 1..1000 Index entries for linear recurrences with constant coefficients, signature (3,-2,0,0,-1,1). FORMULA G.f.: (x^5-3*x^4+2*x-1)*x / ((x^4+x^3+x^2+x-1)*(x-1)^2 ). a(n) = +3*a(n-1) -2*a(n-2) -a(n-5) +a(n-6). a(n) = 5/9-n/3 +(10*A000078(n) +17*A000078(n+1) +21*A000078(n+2) -14*A000078(n+3))/9. - R. J. Mathar, Oct 16 2011 MAPLE a:= n-> (Matrix(6, (i, j)-> `if`(i=j-1, 1, `if`(i=6, [1, -1, 0, 0, -2, 3][j], 0)))^n. <<-1, 1, 1, 1, 1, 4>>)[1, 1]: seq(a(n), n=1..50); # Alois P. Heinz, Oct 15 2011 MATHEMATICA nn = 40; a[1] = a[2] = a[3] = a[4] = 1; Do[a[n] = a[n - 1] + a[n - 2] + a[n - 3] + a[n - 4] + (n - 5), {n, 5, nn}]; Table[a[n], {n, nn}] (* T. D. Noe, Oct 07 2011 *) RecurrenceTable[{a[1]==a[2]==a[3]==a[4]==1, a[n]==a[n-1]+a[n-2]+a[n-3]+a[n-4]+(n-5)}, a, {n, 40}] (* or *) LinearRecurrence[{3, -2, 0, 0, -1, 1}, {1, 1, 1, 1, 4, 8}, 40] (* Harvey P. Dale, Aug 25 2014 *) CROSSREFS Cf. A000126, A196787. Sequence in context: A172042 A145108 A108569 * A111073 A298807 A005934 Adjacent sequences:  A196872 A196873 A196874 * A196876 A196877 A196878 KEYWORD nonn,easy AUTHOR Aditya Subramanian, Oct 07 2011 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 March 31 03:48 EDT 2020. Contains 333136 sequences. (Running on oeis4.)