OFFSET
1,3
LINKS
FORMULA
G.f.: 2*x^3*(1 + x^2)*(1 - 4*x + 6*x^2 - 5*x^3 + x^4 + 2*x^5 + 2*x^6 - 2*x^7) / ((1 - x)^2*(1 - x - x^2)*(1 - 2*x + x^2 - x^3)*(1 - x - x^2 - x^3)) (conjectured). - Colin Barker, Jun 07 2017
EXAMPLE
For n = 5 the 12 such strings are {00100,00101,00111,01000,01001,01101} and their binary complements.
CROSSREFS
KEYWORD
nonn
AUTHOR
Jeffrey Shallit, Mar 20 2017
EXTENSIONS
a(21)-a(37) from Lars Blomberg, Jun 06 2017
STATUS
approved