OFFSET
0,5
COMMENTS
Diagonal sums of number triangle A115356.
LINKS
Index entries for linear recurrences with constant coefficients, signature (-1,0,1,1).
FORMULA
G.f.: (1+2*x+2*x^2)/(1+x-x^3-x^4).
a(n) = -a(n-1)+a(n-3)+a(n-4).
a(n) = -cos(2*Pi*n/3+Pi/6)/sqrt(3)+sin(2*Pi*n/3+Pi/6)/3+(-1)^n/2+5/6.
Sequence shifted right by 2 is additive with a(p^e) = 1 if p = 2 or 3, 0 otherwise.
MATHEMATICA
PadRight[{}, 120, {1, 1, 1, 0, 2, 0}] (* or *) LinearRecurrence[{-1, 0, 1, 1}, {1, 1, 1, 0}, 120] (* Harvey P. Dale, Jan 28 2015 *)
CROSSREFS
KEYWORD
easy,nonn
AUTHOR
Paul Barry, Jan 21 2006
STATUS
approved