OFFSET
1,2
COMMENTS
See A211701 for a discussion and guide to related sequences.
LINKS
Index entries for linear recurrences with constant coefficients, signature (0, 0, 1, 1, 0, 0, -1).
FORMULA
a(n) = a(n-3) + a(n-4) - a(n-7) for n>=8.
G.f.: x*(1 + 3*x + 5*x^2 + 7*x^3 + 5*x^4 + 4*x^5)/((1 - x)^2*(1 + 2*x + 3*x^2 + 3*x^3 + 2*x^4 + x^5)). - Ilya Gutkovskiy, Feb 24 2017
MATHEMATICA
f[n_, m_] := Sum[Floor[n/k], {k, 1, m}]
t = Table[f[n, 4], {n, 1, 90}] (* A211703 *)
FindLinearRecurrence[t]
LinearRecurrence[{0, 0, 1, 1, 0, 0, -1}, {1, 3, 5, 8, 9, 12, 13}, 62] (* Ray Chandler, Aug 02 2015 *)
CROSSREFS
KEYWORD
nonn
AUTHOR
Clark Kimberling, Apr 19 2012
STATUS
approved