login

Year-end appeal: Please make a donation to the OEIS Foundation to support ongoing development and maintenance of the OEIS. We are now in our 61st year, we have over 378,000 sequences, and we’ve reached 11,000 citations (which often say “discovered thanks to the OEIS”).

a(n) = (12*n+9)^3.
0

%I #11 Apr 06 2016 16:16:30

%S 729,9261,35937,91125,185193,328509,531441,804357,1157625,1601613,

%T 2146689,2803221,3581577,4492125,5545233,6751269,8120601,9663597,

%U 11390625,13312053,15438249,17779581,20346417

%N a(n) = (12*n+9)^3.

%H <a href="/index/Rec#order_04">Index entries for linear recurrences with constant coefficients</a>, signature (4,-6,4,-1).

%F G.f. 27*(27+235*x+121*x^2+x^3)/(x-1)^4. a(n) = 27*A016839(n). - _R. J. Mathar_, Dec 03 2015

%t (12*Range[0,30]+9)^3 (* or *) LinearRecurrence[{4,-6,4,-1},{729,9261,35937,91125},30] (* _Harvey P. Dale_, Apr 06 2016 *)

%o (PARI) a(n) = (12*n+9)^3; \\ _Altug Alkan_, Dec 03 2015

%K nonn,easy

%O 0,1

%A _N. J. A. Sloane_.