OFFSET
0,2
COMMENTS
a(n+1) = 4*A097163(n). - Zerinvary Lajos, Mar 17 2008
See A133628 for an essentially identical sequence. - R. J. Mathar, Jun 08 2008
LINKS
FORMULA
a(n) = 5*2^n/2 - (-2)^n/6 - 4/3;
a(n) = a(n-1) + 4a(n-2) - 4a(n-3).
G.f. ( 1+3*x ) / ( (x-1)*(2*x+1)*(2*x-1) ). - R. J. Mathar, Jul 06 2011
MAPLE
a[0]:=0:a[1]:=1:for n from 2 to 100 do a[n]:=4*a[n-2]+4 od: seq(a[n], n=1..31); # Zerinvary Lajos, Mar 17 2008
MATHEMATICA
CoefficientList[Series[(1+3x)/((1-x)(1-4x^2)), {x, 0, 50}], x] (* or *) LinearRecurrence[{1, 4, -4}, {1, 4, 8}, 50] (* Harvey P. Dale, Jul 11 2023 *)
CROSSREFS
KEYWORD
easy,nonn
AUTHOR
Paul Barry, Jul 30 2004
STATUS
approved