A135332 - OEIS

%I #23 Jan 02 2024 08:57:18

%S 1,9,10,74,75,291,292,804,805,1805,1806,3534,3535,6279,6280,10376,

%T 10377,16209,16210,24210,24211,34859,34860,48684,48685,66261,66262,

%U 88214,88215,115215,115216,147984,147985,187289,187290,233946,233947,288819

%N a(1)=1; for n>1, a(n) = a(n-1) + n^0 if n odd, a(n) = a(n-1) + n^3 if n is even.

%H G. C. Greubel, <a href="/A135332/b135332.txt">Table of n, a(n) for n = 1..1000</a>

%H <a href="/index/Rec#order_09">Index entries for linear recurrences with constant coefficients</a>, signature (1, 4, -4, -6, 6, 4, -4, -1, 1).

%F From _R. J. Mathar_, Feb 22 2009: (Start)

%F a(n) = a(n-1) + 4*a(n-2) - 4*a(n-3) - 6*a(n-4) + 6*a(n-5) + 4*a(n-6) - 4*a(n-7)  - a(n-8) + a(n-9).

%F G.f.: x*(1 + 8*x - 3*x^2 + 32*x^3 + 3*x^4 +8*x^5 -x^6)/((1+x)^4*(1-x)^5). (End)

%t LinearRecurrence[{1,4,-4,-6,6,4,-4,-1,1},{1,9,10,74,75,291,292,804,805},40] (* _Harvey P. Dale_, Nov 28 2014 *)

%Y Cf. A000027, A000217, A000330, A000537, A000538, A000539, A136047, A140113.

%K nonn

%O 1,2

%A _Artur Jasinski_, May 12 2008