A036405 a(n) = ceiling(n^2/7).

0, 1, 1, 2, 3, 4, 6, 7, 10, 12, 15, 18, 21, 25, 28, 33, 37, 42, 47, 52, 58, 63, 70, 76, 83, 90, 97, 105, 112, 121, 129, 138, 147, 156, 166, 175, 186, 196, 207, 218, 229, 241, 252, 265, 277, 290, 303, 316, 330, 343, 358, 372, 387, 402, 417, 433, 448

Offset

0,4

Links

Table of n, a(n) for n=0..56.

Index entries for linear recurrences with constant coefficients, signature (2,-1,0,0,0,0,1,-2,1). [R. J. Mathar, Jul 06 2010]

Formula

a(n) = +2*a(n-1) -a(n-2) +a(n-7) -2*a(n-8) +a(n-9). G.f.: x*(1+x)*(x^2-x+1)*(x^4-x^3+x^2-x+1) / ( (x^6+x^5+x^4+x^3+x^2+x+1)*(1-x)^3 ). [R. J. Mathar, Jul 06 2010]

Maple

A036405:=n->ceil(n^2/7): seq(A036405(n), n=0..100); # Wesley Ivan Hurt, Jan 16 2017

Mathematica

Ceiling[Range[0, 60]^2/7] (* or *) LinearRecurrence[{2, -1, 0, 0, 0, 0, 1, -2, 1}, {0, 1, 1, 2, 3, 4, 6, 7, 10}, 60] (* Harvey P. Dale, Jun 23 2015 *)

Crossrefs

Sequence in context: A163180 A341270 A091515 * A051424 A308632 A137606

Adjacent sequences: A036402 A036403 A036404 * A036406 A036407 A036408

Keyword

nonn,easy

Author

N. J. A. Sloane

Status

approved