OFFSET
0,2
LINKS
FORMULA
a(n) = 9*a(n-1) - 8*a(n-3) for n>2, a(0) = 1, a(1) = 8, a(2) = 71.
a(n) = 8*a(n-1) + 8*a(n-2) - 1.
G.f.: (1-x-x^2)/((1-x)*(1-8*x-8*x^2)).
a(n) = Sum_{k=0..n} A370174(n,k)*7^k.
a(n) = (7*(8-3*sqrt(6))*(4-2*sqrt(6))^n + 7*(8+3*sqrt(6))*(4+2*sqrt(6))^n + 8)/120.
MATHEMATICA
LinearRecurrence[{9, 0, -8}, {1, 8, 71}, 21] (* James C. McMahon, Apr 21 2024 *)
CROSSREFS
KEYWORD
nonn,easy
AUTHOR
Philippe Deléham, Apr 02 2024
STATUS
approved