OFFSET
0,4
LINKS
Michael De Vlieger, Table of n, a(n) for n = 0..3899
Félix Balado and Guénolé C. M. Silvestre, Systematic Enumeration of Fundamental Quantities Involving Runs in Binary Strings, arXiv:2602.10005 [math.CO], 2026. See pp. 38, 105.
Index entries for linear recurrences with constant coefficients, signature (2,3,-6,-2,4,-1).
FORMULA
G.f.: ((1 - x^2) * x^2)/(1 - x - 2 * x^2 + x^3)^2.
EXAMPLE
a(3)=2 because of the strings 011 and 110.
MATHEMATICA
CoefficientList[Series[((1 - x^2) * x^2)/(1 - x - 2 * x^2 + x^3)^2, {x, 0, 35}], x] (* Stefano Spezia, Jun 02 2025 *)
CROSSREFS
KEYWORD
nonn,easy
AUTHOR
Félix Balado, May 31 2025
STATUS
approved