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 A347255 #16 Sep 29 2021 04:02:15
%S A347255 0,3,25,281,2941,30596,315385,3231664,32972224,335346193,3402373313,
%T A347255 34454358909,348373701706,3518101287286,35491654274101
%N A347255 Number of positive integers with n digits that are the product of two integers ending with 4.
%C A347255 a(n) is the number of n-digit numbers in A347253.
%F A347255 a(n) < A052268(n).
%F A347255 Conjecture: lim_{n->infinity} a(n)/a(n-1) = 10.
%o A347255 (Python)
%o A347255 def a(n):
%o A347255 lo, hi = 10**(n-1), 10**n
%o A347255 return len(set(a*b for a in range(4, hi//4+1, 10) for b in range(a, hi//a+1, 10) if lo <= a*b < hi))
%o A347255 print([a(n) for n in range(1, 9)]) # _Michael S. Branicky_, Aug 24 2021
%Y A347255 Cf. A017341, A052268, A347253.
%Y A347255 Cf. A346509 (ending with 1), A346952 (ending with 3), A337855 (ending with 5), A337856 (ending with 6).
%K A347255 nonn,base,hard,more
%O A347255 1,2
%A A347255 _Stefano Spezia_, Aug 24 2021
%E A347255 a(9)-a(11) from _Michael S. Branicky_, Aug 25 2021
%E A347255 a(12)-a(15) from _Martin Ehrenstein_, Sep 29 2021