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 A275850 #13 Aug 18 2016 08:55:02
%S A275850 0,0,1,1,1,0,2,2,2,2,1,1,2,1,1,1,2,1,2,1,1,1,1,0,3,3,3,3,2,2,3,3,3,3,
%T A275850 2,2,2,2,2,2,2,2,2,2,2,2,1,1,3,2,2,2,3,2,2,2,2,2,2,2,3,2,2,2,3,2,2,1,
%U A275850 1,1,2,1,3,2,2,2,2,1,2,2,2,2,1,1,2,1,1,1,2,1,3,2,2,2,2,1,3,2,2,2,2,1,2,2,2,2,1,1,2,1,1,1,2,1,2,1,1,1,1,0,4
%N A275850 Number of digits in range [1..A084558(n)] that do not occur in factorial base representation of n: a(n) = A084558(n) - A275806(n).
%H A275850 Antti Karttunen, <a href="/A275850/b275850.txt">Table of n, a(n) for n = 0..40320</a>
%H A275850 <a href="/index/Fa#facbase">Index entries for sequences related to factorial base representation</a>
%F A275850 a(n) = A084558(n) - A275806(n).
%F A275850 Other identities. For all n >= 0:
%F A275850 a(n) = A275849(A225901(n)).
%e A275850 For n=6 ("100" in factorial base representation A007623) there are two digits in interval [1..A084558(6)] = [1..3] that are not used, namely 2 and 3, thus a(6)=2.
%e A275850 For n=12 ("200") there are also two digits in interval [1..3] that are not used, namely 1 and 3, thus a(12)=2.
%e A275850 For n=23 ("321") all the digits in interval [1..3] are in use, thus a(23)=0.
%o A275850 (Scheme) (define (A275850 n) (- (A084558 n) (A275806 n)))
%Y A275850 Cf. A084558, A275806.
%Y A275850 Cf. A033312 (indices of zeros).
%Y A275850 Cf. also A007623, A225901, A275849.
%K A275850 nonn,base
%O A275850 0,7
%A A275850 _Antti Karttunen_, Aug 15 2016