A056865 a(n) = floor(n^2/10).

0, 0, 0, 0, 1, 2, 3, 4, 6, 8, 10, 12, 14, 16, 19, 22, 25, 28, 32, 36, 40, 44, 48, 52, 57, 62, 67, 72, 78, 84, 90, 96, 102, 108, 115, 122, 129, 136, 144, 152, 160, 168, 176, 184, 193, 202, 211, 220, 230, 240, 250, 260, 270, 280, 291, 302, 313, 324

Offset: 0

Author

N. J. A. Sloane, Sep 02 2000

Keywords

• nonn
• easy

Links

• Ray Chandler, Table of n, a(n) for n = 0..1000
• Index entries for linear recurrences with constant coefficients, signature (2,-1,0,0,0,0,0,0,0,1,-2,1).

Crossrefs

Cf. A056864.

Cf. A000290, A007590, A000212, A002620, A118015, A056827, A056834, A130519, A056838.

Programs

Maple

A056865 := proc(n)
    floor(n^2/10) ;
end proc:
seq(A056865(n),n=0..100) ; # R. J. Mathar, Mar 08 2016

Mathematica

Floor[Range[0,60]^2/10] (* or *) LinearRecurrence[{2,-1,0,0,0,0,0,0,0,1,-2,1},{0,0,0,0,1,2,3,4,6,8,10,12},60] (* Harvey P. Dale, Jun 29 2022 *)

PARI

a(n) = n^2\10; \\ Michel Marcus, Mar 08 2016

Formula

G.f.: -x^4*(1+x^4) / ( (1+x)*(x^4-x^3+x^2-x+1)*(x^4+x^3+x^2+x+1)*(x-1)^3 ). - R. J. Mathar, Mar 08 2016