A056834 a(n) = floor(n^2/7).

0, 0, 0, 1, 2, 3, 5, 7, 9, 11, 14, 17, 20, 24, 28, 32, 36, 41, 46, 51, 57, 63, 69, 75, 82, 89, 96, 104, 112, 120, 128, 137, 146, 155, 165, 175, 185, 195, 206, 217, 228, 240, 252, 264, 276, 289, 302, 315, 329, 343, 357, 371, 386, 401, 416, 432, 448

Offset

0,5

Links

Vincenzo Librandi, Table of n, a(n) for n = 0..1000

Index entries for linear recurrences with constant coefficients, signature (2,-1,0,0,0,0,1,-2,1).

Formula

a(n) = +2*a(n-1) -a(n-2) +a(n-7) -2*a(n-8) +a(n-9).

G.f.: -x^3*(1+x)*(x^2-x+1) / ( (x^6+x^5+x^4+x^3+x^2+x+1)*(x-1)^3 ).

Mathematica

Floor[(Range[0, 60]^2)/7] (* or *) LinearRecurrence[{2, -1, 0, 0, 0, 0, 1, -2, 1}, {0, 0, 0, 1, 2, 3, 5, 7, 9}, 60] (* Harvey P. Dale, Jul 21 2014 *)
CoefficientList[Series[-x^3 (1 + x) (x^2 - x + 1)/((x^6 + x^5 + x^4 + x^3 + x^2 + x + 1) (x - 1)^3), {x, 0, 100}], x] (* Vincenzo Librandi, Jul 22 2014 *)

Prog

(PARI) a(n) = n^2\7; \\ Michel Marcus, Mar 03 2022

Crossrefs

Cf. A000290, A007590, A000212, A002620, A118015, A056827, A130519, A056838, A056865.

Sequence in context: A241907 A065130 A023535 * A183140 A286283 A139282

Adjacent sequences: A056831 A056832 A056833 * A056835 A056836 A056837

Keyword

nonn,easy

Author

N. J. A. Sloane, Sep 02 2000

Status

approved