OFFSET
0,3
COMMENTS
LINKS
Bruno Berselli, Table of n, a(n) for n = 0..1000
Index entries for linear recurrences with constant coefficients, signature (1,1,0,-1,-1,1).
FORMULA
G.f.: x*(1 + 3*x + 2*x^2 - 2*x^4) / ((1 + x)*(1 + x + x^2)*(1 - x)^3).
a(n) = a(n-1) + a(n-2) - a(n-4) - a(n-5) + a(n-6).
a(n) = (2*n*(2*n+9) - 2*(-1)^floor(2*(n-1)/3) + 3*(-1)^n - 5)/12.
a(n+2) - a(n) = A004772(n+4).
Also: a(n) = n + floor(n/2) + floor(n^2/3).
MATHEMATICA
Table[n + Floor[n/2 + n^2/3], {n, 0, 60}]
PROG
(Magma) [n+Floor(n/2+n^2/3): n in [0..60]];
CROSSREFS
KEYWORD
nonn,easy
AUTHOR
Bruno Berselli, Feb 06 2014
STATUS
approved