A037588 Base 9 digits are, in order, the first n terms of the periodic sequence with initial period 3,1.

3, 28, 255, 2296, 20667, 186004, 1674039, 15066352, 135597171, 1220374540, 10983370863, 98850337768, 889653039915, 8006877359236, 72061896233127, 648557066098144, 5837013594883299

Offset

1,1

Links

Table of n, a(n) for n=1..17.

Index entries for linear recurrences with constant coefficients, signature (9,1,-9).

Formula

G.f.: x*(3+x) / ( (x-1)*(9*x-1)*(1+x) ). - R. J. Mathar, Apr 27 2015

a(n) = 7*9^n/20 -1/4 +(-1)^(n+1)/10. - R. J. Mathar, Apr 27 2015

Mathematica

With[{c=PadLeft[{}, 20, {3, 1}]}, Table[FromDigits[Take[c, n], 9], {n, 20}]] (* Harvey P. Dale, Oct 15 2011 *)

Crossrefs

Sequence in context: A037777 A037665 A037784 * A307885 A076723 A198887

Adjacent sequences: A037585 A037586 A037587 * A037589 A037590 A037591

Keyword

nonn,base,easy

Author

Clark Kimberling

Status

approved