|
%I #21 Dec 28 2016 11:55:24
%S 1,15,240,3840,61440,983040,15728640,251658240,4026531840,64424509440,
%T 1030792151040,16492674416640,263882790666240,4222124650659840,
%U 67553994410557440,1080863910568919040,17293822569102704640,276701161105643274240,4427218577690292387840
%N G.f.: (1-x)/(1-16x).
%H <a href="/index/Rec">Index entries for linear recurrences with constant coefficients</a>, signature (16).
%F a(n) = 15*16^(n-1)+0^n/16.
%F a(n) = sum{j=0..3, sum{k=0..n, C(4n+j, 4k) }}.
%F a(n) = (A070775(n) + A090407(n) + A001025(n) + A090408(n))/4.
%t Join[{1, a = 15}, Table[a=16*a, {n,0,30}]] (* _Vladimir Joseph Stephan Orlovsky_, Jun 10 2011 *)
%t Join[{1},NestList[16#&,15,20]] (* _Harvey P. Dale_, Dec 28 2016 *)
%o (PARI) a(n)=if(n,15<<(4*n-4),1) \\ _Charles R Greathouse IV_, Jun 10 2011
%Y Cf. A090409.
%K easy,nonn
%O 0,2
%A _Paul Barry_, Nov 30 2003
|
