OFFSET
0,2
COMMENTS
Permutation of the nonnegative numbers.
LINKS
FORMULA
a(3*n) = 4*n, a(3*n+1) = 4*n+2, a(3*n+2) = 2*n+1.
a(n) = 2*a(n-3) - a(n-6) for n >= 6.
a(n) = A006369(n+1) - 1.
G.f.: x*(2+x+4*x^2+2*x^3+x^4)/(1-x^3)^2.
E.g.f.: exp(-x/2)*(exp(3*x/2)*(10*x + 1) + (2*x - 1)*cos(sqrt(3)*x/2) + sqrt(3)*(3 - 2*x)*sin(sqrt(3)*x/2))/9. - Stefano Spezia, Nov 12 2023
MATHEMATICA
LinearRecurrence[{0, 0, 2, 0, 0, -1}, {0, 2, 1, 4, 6, 3}, 100] (* Paolo Xausa, Nov 14 2023 *)
CROSSREFS
KEYWORD
nonn,easy
AUTHOR
Philippe Deléham, Nov 12 2023
STATUS
approved