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 A263480 #25 Oct 25 2015 07:00:05
%S A263480 1,13,141,1017,5671,36695,274919,1905346,11961897,70484777,393138130,
%T A263480 2099243511,11182203514,61491912211,342906589613,1849155959180,
%U A263480 9348828582989,44293571012946,201612389814511,924729895792089,4608967720196409,26924559367277143
%N A263480 Total number of n-digit positive integers with multiplicative digital root value 6.
%C A263480 First differences of A263474.
%H A263480 Hiroaki Yamanouchi, <a href="/A263480/b263480.txt">Table of n, a(n) for n = 1..50</a>
%F A263480 A263476(n) + A000012(n) + A263477(n) + A000027(n) + A263478(n) + A263479(n) + a(n) + A000027(n) + A263481(n) + A000217(n) = A052268(n).
%t A263480 Last /@ Tally@ IntegerLength@ Select[Range@ 1000000, FixedPoint[Times @@ IntegerDigits@ # &, #] == 6 &] (* _Michael De Vlieger_, Oct 21 2015 *)
%o A263480 (PARI) t(k) = {while(k>9, k=prod(i=1, #k=digits(k), k[i])); k}
%o A263480 a(n) = sum(i=10^(n-1), 10^n - 1, if(t(i) == 6, 1, 0)); \\ _Altug Alkan_, Oct 19 2015
%Y A263480 Cf. A031347, A034053, A263474.
%K A263480 nonn,base
%O A263480 1,2
%A A263480 _Martin Renner_, Oct 19 2015
%E A263480 a(9)-a(22) from _Hiroaki Yamanouchi_, Oct 25 2015