This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.
%I A083894 #18 Jan 04 2024 03:24:11
%S A083894 0,0,0,0,0,0,1,0,0,0,0,0,0,1,0,0,1,0,0,0,1,0,0,0,0,0,1,1,0,0,0,0,0,1,
%T A083894 1,0,1,0,0,0,0,1,0,0,0,0,1,0,1,0,1,0,0,1,0,1,1,0,0,0,0,0,1,0,0,0,1,1,
%U A083894 0,2,1,1,1,2,1,1,2,0,0,0,1,0,0,1,1,0,0,0,0,0,1,0,0,1,0,0,0,1,0,0,0,1,0,0,1
%N A083894 Number of divisors of n with largest digit = 7 (base 10).
%H A083894 Robert Israel, <a href="/A083894/b083894.txt">Table of n, a(n) for n = 1..10000</a>
%F A083894 a(n) = A000005(n) - A083888(n) - A083889(n) - A083890(n) - A083891(n) - A083892(n) - A083893(n) - A083895(n) - A083896(n) = A083902(n) - A083901(n).
%F A083894 Asymptotic mean: Limit_{m->oo} (1/m) * Sum_{k=1..m} a(k) = Sum_{k>=1} 1/A283610(k) = 3.96819589328234218540... . - _Amiram Eldar_, Jan 04 2024
%e A083894 n=119, 2 of the 4 divisors of 119 have largest digit =7: {7,17}, therefore a(119)=2.
%p A083894 f:= proc(n) nops(select(t -> max(convert(t, base, 10))=d, numtheory:-divisors(n))) end proc:
%p A083894 d:= 7:
%p A083894 map(f, [$1..200]); # _Robert Israel_, Oct 06 2019
%t A083894 Table[Count[Divisors[n],_?(Max[IntegerDigits[#]]==7&)],{n,120}] (* _Harvey P. Dale_, Oct 16 2021 *)
%Y A083894 Cf. A054055, A000005, A083902, A083888, A083889, A083890, A083891, A083892, A083893, A083895, A083896, A283610.
%K A083894 nonn,base
%O A083894 1,70
%A A083894 _Reinhard Zumkeller_, May 08 2003