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A083898 Number of divisors of n with largest digit <= 3 (base 10). 5

%I #11 Jan 04 2024 01:48:23

%S 1,2,2,2,1,3,1,2,2,3,2,4,2,2,2,2,1,3,1,4,3,4,2,4,1,3,2,2,1,5,2,3,4,2,

%T 1,4,1,2,3,4,1,4,1,4,2,3,1,4,1,3,2,3,1,3,2,2,2,2,1,7,1,3,3,3,2,6,1,2,

%U 3,3,1,4,1,2,2,2,2,4,1,4,2,2,1,5,1,2,2,4,1,5,2,3,3,2,1,5,1,2,4,5,2,4,2,3,3

%N Number of divisors of n with largest digit <= 3 (base 10).

%H Harvey P. Dale, <a href="/A083898/b083898.txt">Table of n, a(n) for n = 1..1000</a>

%F a(n) = A083897(n) + A083890(n) = A083899(n) - A083891(n).

%F Asymptotic mean: Limit_{m->oo} (1/m) * Sum_{k=1..m} a(k) = Sum_{k>=1} 1/A007090(k) = 2.93694402167748963905... . - _Amiram Eldar_, Jan 04 2024

%t Table[Count[Divisors[n],_?(Total[Most[Drop[DigitCount[#],3]]]==0&)],{n,120}] (* _Harvey P. Dale_, Dec 21 2018 *)

%Y Cf. A054055, A000005, A007090, A083890, A083891, A083897, A083899.

%K nonn,base

%O 1,2

%A _Reinhard Zumkeller_, May 08 2003

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Last modified April 18 20:21 EDT 2024. Contains 371781 sequences. (Running on oeis4.)