OFFSET
1,2
COMMENTS
LINKS
Vincenzo Librandi, Table of n, a(n) for n = 1..1000
Index entries for linear recurrences with constant coefficients, signature (0,6,0,-9,0,4).
FORMULA
G.f.: x*(1+4*x-3*x^2-8*x^3-4*x^4+4*x^5)/((1-x)^2*(1+x)^2*(1-2x)*(1+2x)). - Philippe Deléham, Apr 01 2013
a(n) = 6*a(n-2) -9*a(n-4) + 4*a(n-6) with a(1) = 1, a(2) = 4, a(3) = 3, a(4) = 16, a(5) = 5, a(6) = 64. - Philippe Deléham, Apr 01 2013
MATHEMATICA
Table[ If[ OddQ[n], n, 4^(n/2)], {n, 1, 31}] (* Jean-François Alcover, Apr 02 2013 *)
CoefficientList[Series[(1 + 4 x - 3 x^2 - 8 x^3 - 4 x^4 + 4 x^5) / ((1 - x)^2 (1 + x)^2 (1 - 2 x) (1 + 2 x)), {x, 0, 35}], x] (* Vincenzo Librandi, Jul 20 2013 *)
LinearRecurrence[{0, 6, 0, -9, 0, 4}, {1, 4, 3, 16, 5, 64}, 40] (* Harvey P. Dale, Jul 30 2018 *)
CROSSREFS
KEYWORD
nonn,easy,less
AUTHOR
Paul Curtz, Mar 29 2013
EXTENSIONS
Conjecture about A132049(n)/a(n) modified by Jean-François Alcover, Apr 12 2013
STATUS
approved