OFFSET
0,3
LINKS
Index entries for linear recurrences with constant coefficients, signature (0,5,0,-4).
FORMULA
For n>9, a(n)=4*a(n-2) + (a(n-2) mod 4).
a(n) = 5*a(n-2)-4*a(n-4) for n>5; g.f.: x*(32*x^10+16*x^9-12*x^8-12*x^7-17*x^6-x^4-6*x^3-2*x^2+2*x+1) / ((x-1)*(x+1)*(2*x-1)*(2*x+1)). - Colin Barker, Sep 13 2014
EXAMPLE
Written in base 4 the sequence appears as 0, 1, 2, 3, 10, 22, 30, 111, 200, 311, 2000, 3111, 20000, 31111, 200000, 311111, 2000000, 3111111, etc. So a(9)=311 base 4 =53 base 10.
MATHEMATICA
LinearRecurrence[{0, 5, 0, -4}, {0, 1, 2, 3, 4, 10, 12, 21, 32, 53, 128, 213}, 40] (* Harvey P. Dale, Apr 27 2020 *)
CROSSREFS
KEYWORD
base,easy,nonn
AUTHOR
Henry Bottomley, Dec 28 2000
STATUS
approved