OFFSET
0,1
COMMENTS
The path is on the slope after 0, 21, 42, 63, 84,... steps (A008603), which gives the simple C-finite recurrence. - R. J. Mathar, May 28 2025
FORMULA
a(n) = a(n-21). - R. J. Mathar, May 28 2025
G.f.: -x^2*(1+x^2)*(x^8-x^6+x^4-x^2+1)*(x^4-x^3+x^2-x+1)*(1+x+x^2+x^3+x^4) / ( (x-1)*(1+x^6+x^5+x^4+x^3+x^2+x)*(1+x+x^2)*(1-x+x^3-x^4+x^6-x^8+x^9-x^11+x^12) ). - R. J. Mathar, May 28 2025
CROSSREFS
KEYWORD
nonn,easy
AUTHOR
N. J. A. Sloane, Jan 13 2009
STATUS
approved
