A272576 - OEIS

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A272576

a(n) = f(10, f(9, n)), where f(k,m) = floor(m*k/(k-1)).

0, 1, 2, 3, 4, 5, 6, 7, 10, 11, 12, 13, 14, 15, 16, 17, 20, 21, 22, 23, 24, 25, 26, 27, 30, 31, 32, 33, 34, 35, 36, 37, 40, 41, 42, 43, 44, 45, 46, 47, 50, 51, 52, 53, 54, 55, 56, 57, 60, 61, 62, 63, 64, 65, 66, 67, 70, 71, 72, 73, 74, 75, 76, 77, 80, 81, 82, 83, 84, 85, 86, 87, 90

(list; graph; refs; listen; history; text; internal format)

OFFSET

0,3

COMMENTS

Also, numbers not ending with the digit 8 or 9.

The initial terms coincide with those of A007094 and A039155. First disagreement is after 77 (index 63): a(64) = 80, A007094(64) = 100 and A039155(65) = 89.

LINKS

Table of n, a(n) for n=0..72.

Index entries for linear recurrences with constant coefficients, signature (1,0,0,0,0,0,0,1,-1).

Index entries for 10-automatic sequences.

FORMULA

G.f.: x*(1 + x + x^2 + x^3 + x^4 + x^5 + x^6 + 3*x^7)/((1 + x)*(1 - x)^2*(1 + x^2) *(1 + x^4)).

a(n) = a(n-1) + a(n-8) - a(n-9).

a(n) = 1.25n + O(1). - Charles R Greathouse IV, Nov 07 2022

MAPLE

f := (k, m) -> floor(m*k/(k-1)):

a := n -> f(10, f(9, n)):

seq(a(n), n = 0..72); # Peter Luschny, May 03 2016