|
%I #22 Jun 13 2019 08:41:53
%S 1,3,11,17,38,50,90,110,175,205,301,343,476,532,708,780,1005,1095,
%T 1375,1485,1826,1958,2366,2522,3003,3185,3745,3955,4600,4840,5576,
%U 5848,6681,6987,7923,8265,9310,9690,10850,11270,12551,13013,14421,14927,16468,17020,18700,19300
%N a(n) = 1*t(n) + 2*t(n-1) + ... + k*t(n+1-k), where k=floor((n+1)/2) and t(n)=2*n+1 (odd numbers).
%H <a href="/index/Rec#order_07">Index entries for linear recurrences with constant coefficients</a>, signature (1,3,-3,-3,3,1,-1)
%F G.f.: x*(1+2*x+5*x^2) / ( (1+x)^3*(1-x)^4 ). - _R. J. Mathar_, Oct 04 2014
%F a(n) = (8*n^3+24*n^2+10*n-3-3*(2*n^2+2*n-1)*(-1)^n)/48. - _Luce ETIENNE_, Nov 21 2014
%t Rest@ CoefficientList[Series[x (1 + 2 x + 5 x^2)/((1 + x)^3*(1 - x)^4), {x, 0, 48}], x] (* _Michael De Vlieger_, Jun 12 2019 *)
%K nonn,easy
%O 1,2
%A _Clark Kimberling_
%E Title simplified by _Sean A. Irvine_, Jun 12 2019
|
