A011870 - OEIS

%I #13 Dec 27 2021 22:08:11

%S 0,0,0,0,0,1,1,2,3,4,5,6,7,9,10,12,14,16,18,20,22,24,27,29,32,35,38,

%T 41,44,47,51,54,58,62,66,70,74,78,82,87,91,96,101,106,111,116,121,127,

%U 132,138,144,150,156,162,168,174,181,187,194,201,208,215,222,229,237,244,252

%N a(n) = floor(n*(n-1)/17).

%H <a href="/index/Rec#order_19">Index entries for linear recurrences with constant coefficients</a>, signature (2, -1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, -2, 1).

%F G.f.: x^5(1-x+x^2)(1+x^8)/((1-x)^2*(1-x^17)). - _R. J. Mathar_, Jan 05 2009

%t Table[Floor[(n(n-1))/17],{n,0,70}] (* or *) LinearRecurrence[{2,-1,0,0,0,0,0,0,0,0,0,0,0,0,0,0,1,-2,1},{0,0,0,0,0,1,1,2,3,4,5,6,7,9,10,12,14,16,18},70] (* _Harvey P. Dale_, Apr 11 2018 *)

%K nonn

%O 0,8

%A _N. J. A. Sloane_