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%I A217395 #30 Sep 11 2024 11:45:08
%S A217395 3,30,31,32,33,34,35,36,37,38,39,300,301,302,303,304,305,306,307,308,
%T A217395 309,310,311,312,313,314,315,316,317,318,319,320,321,322,323,324,325,
%U A217395 326,327,328,329,330,331,332,333,334,335,336,337,338,339,340,341,342
%N A217395 Numbers starting with 3.
%C A217395 The lower and upper asymptotic densities of this sequence are 1/27 and 5/18, respectively. - _Amiram Eldar_, Feb 27 2021
%H A217395 Jeremy Gardiner, <a href="/A217395/b217395.txt">Table of n, a(n) for n = 1..1111</a>
%H A217395 <a href="/index/Ar#10-automatic">Index entries for 10-automatic sequences</a>.
%F A217395 a(n) = n + (26*10^floor(log_10(9*n-8))-8)/9. - _Alan Michael Gómez Calderón_, May 16 2023
%t A217395 Select[Range[1000], IntegerDigits[#][[1]] == 3 &] (* _T. D. Noe_, Oct 02 2012 *)
%o A217395 (Python)
%o A217395 def agen():
%o A217395   yield 3
%o A217395   digits, adder = 1, 30
%o A217395   while True:
%o A217395     for i in range(10**digits): yield adder + i
%o A217395     digits, adder = digits+1, adder*10
%o A217395 g = agen()
%o A217395 print([next(g) for i in range(54)]) # _Michael S. Branicky_, Mar 30 2021
%o A217395 (Python)
%o A217395 def A217395(n): return n+26*10**(len(str(9*n-8))-1)//9 # _Chai Wah Wu_, Sep 11 2024
%o A217395 (PARI) a(n) = n + 26*10^logint(9*n,10)\9; \\ _Kevin Ryde_, Mar 30 2021
%Y A217395 Cf. A006092, A011533.
%Y A217395 Subsequences include: A045709, A077328, A077679, A106413, A106423.
%Y A217395 Cf. A131835, A217394, A217397, A217398, A217399, A217400, A217401, A217402.
%K A217395 nonn,base,easy
%O A217395 1,1
%A A217395 _Jeremy Gardiner_, Oct 02 2012

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