%I #28 Nov 07 2022 20:26:35

%S 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,

%T 31,32,33,34,35,36,37,40,41,42,43,44,45,46,47,50,51,52,53,54,55,56,57,

%U 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

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

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

%C 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.

%H <a href="/index/Rec#order_09">Index entries for linear recurrences with constant coefficients</a>, signature (1,0,0,0,0,0,0,1,-1).

%H <a href="/index/Ar#10-automatic">Index entries for 10-automatic sequences</a>.

%F 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)).

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

%F a(n) = 1.25n + O(1). - _Charles R Greathouse IV_, Nov 07 2022

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

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

%p seq(a(n), n = 0..72); # _Peter Luschny_, May 03 2016

%t f[k_, m_] := Floor[m*k/(k-1)];

%t a[n_] := f[10, f[9, n]];

%t Table[a[n], {n, 0, 72}] (* _Jean-François Alcover_, May 09 2016 *)

%t LinearRecurrence[{1,0,0,0,0,0,0,1,-1},{0,1,2,3,4,5,6,7,10},90] (* _Harvey P. Dale_, Jun 22 2017 *)

%o (Magma) k:=10; f:=func<k,m | Floor(m*k/(k-1))>; [f(k,f(k-1,n)): n in [0..70]];

%o (Sage)

%o f = lambda k, m: floor(m*k/(k-1))

%o a = lambda n: f(10, f(9, n))

%o [a(n) for n in range(73)] # _Peter Luschny_, May 03 2016

%o (PARI) is(n)=n%10<8 \\ _Charles R Greathouse IV_, Feb 13 2017

%Y Cf. similar sequences listed in A272574.

%K nonn,easy,base

%O 0,3

%A _Bruno Berselli_, May 03 2016