OFFSET
0,2
LINKS
G. C. Greubel, Table of n, a(n) for n = 0..1000
Index entries for linear recurrences with constant coefficients, signature (4,0,0,1,-4)
FORMULA
a(0)=1, a(n) = 4*a(n-1) if n is not a multiple of 4, otherwise a(n) = 4*a(n-1) + 1. - Vincenzo Librandi, Mar 19 2011
a(n) = 4^(n+4)/255 -1/12 +(-1)^n/20 +(-1)^floor(n/2)*A010685(n)/34. - R. J. Mathar, Mar 19 2011
a(0)=1, a(1)=4, a(2)=16, a(3)=64, a(4)=257, a(n) = 4*a(n-1) + a(n-4) - 4*a(n-5). - Harvey P. Dale, Sep 13 2011
a(n) = floor(64*(2^(2*(n+1))+1)/255). - Tani Akinari, Jul 09 2013
MATHEMATICA
CoefficientList[Series[1/((1-4x)(1-x^4)), {x, 0, 30}], x] (* or *) LinearRecurrence[ {4, 0, 0, 1, -4}, {1, 4, 16, 64, 257}, 31] (* Harvey P. Dale, Sep 13 2011 *)
PROG
(PARI) a(n)=(4^(n+4)+64)\255 \\ Charles R Greathouse IV, Jul 09 2013
CROSSREFS
KEYWORD
easy,nonn
AUTHOR
Paul Barry, May 02 2003
STATUS
approved