OFFSET
1,2
LINKS
FORMULA
G.f.: x*(1+2*x+3*x^2) / ( (x-1)*(9*x-1)*(1+x+x^2) ). - R. J. Mathar, Apr 27 2015
MATHEMATICA
Table[FromDigits[PadRight[{}, n, {1, 2, 3}], 9], {n, 20}] (* or *) LinearRecurrence[{9, 0, 1, -9}, {1, 11, 102, 919}, 20] (* Harvey P. Dale, Nov 16 2024 *)
PROG
(PARI) a(n)=([0, 1, 0, 0; 0, 0, 1, 0; 0, 0, 0, 1; -9, 1, 0, 9]^(n-1)*[1; 11; 102; 919])[1, 1] \\ Charles R Greathouse IV, Feb 13 2017
CROSSREFS
KEYWORD
nonn,base,easy,changed
AUTHOR
STATUS
approved