A144607 Christoffel word of slope 9/11.

0, 0, 1, 0, 1, 0, 1, 0, 1, 0, 0, 1, 0, 1, 0, 1, 0, 1, 0, 1, 0, 0, 1, 0, 1, 0, 1, 0, 1, 0, 0, 1, 0, 1, 0, 1, 0, 1, 0, 1, 0, 0, 1, 0, 1, 0, 1, 0, 1, 0, 0, 1, 0, 1, 0, 1, 0, 1, 0, 1, 0, 0, 1, 0, 1, 0, 1, 0, 1, 0, 0, 1, 0, 1, 0, 1, 0, 1, 0, 1, 0, 0, 1, 0, 1, 0, 1, 0, 1, 0, 0, 1, 0, 1, 0, 1, 0, 1, 0, 1, 0, 0, 1, 0, 1

Offset: 0

Author

N. J. A. Sloane, Jan 13 2009

Keywords

• nonn
• easy

Crossrefs

See A144595 for further details.

Formula

a(n) = a(n-20). - R. J. Mathar, May 30 2025

G.f.: -x^2*(1+x^2+x^4+x^6+x^9+x^11+x^13+x^15+x^17) / ( (x-1)*(1+x^4+x^3+x^2+x)*(1+x)*(1-x+x^2-x^3+x^4)*(1+x^2)*(x^8-x^6+x^4-x^2+1) ). - R. J. Mathar, May 30 2025