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 A136428 #11 Oct 19 2024 15:45:53
%S A136428 1,0,0,1,0,0,0,0,1,7,1,0,0,1,0,0,0,0,1,-3,1,0,0,1,0,0,0,0,1,-3,1,0,0,
%T A136428 1,0,0,0,0,1,7,1,0,0,1,0,0,0,0,1,-3,1,0,0,1,0,0,0,0,1,-3,1,0,0,1,0,0,
%U A136428 0,0,1,-3,1,0,0,1,0,0,0,0,1,-3,1,0,0,1,0,0,0,0,1,7,1,0,0,1,0,0,0,0,1,67,1,0,0,1,0,0,0,0,1,7,1,0,0,1,0,0,0,0,1,-3,1,0,0,1,0
%N A136428 First differences of A064770.
%C A136428 a(10*n+k) = 0 for k = 1, 2, 4, 5, 6, 7;
%C A136428 a(10*n+k) = 1 for k = 0, 3, 8;
%C A136428 a(100*n+10*k+9) = -3 for k = 1, 2, 4, 5, 6, 7;
%C A136428 a(100*n+10*k+9) = 7 for k = 0, 3, 8;
%C A136428 a(1000*n+100*k+99) = -33 for k = 1, 2, 4, 5, 6, 7;
%C A136428 a(1000*n+100*k+99) = 67 for k = 0, 3, 8.
%H A136428 Reinhard Zumkeller, <a href="/A136428/b136428.txt">Table of n, a(n) for n = 0..9999</a>
%F A136428 a(n) = (2*A010052(m mod 10) - 1)*rounded(((1+A010052(m mod 10))*10^k)/3) where n = m*10^k - 1 with m mod 10 > 0.
%o A136428 (Python)
%o A136428 def A136428(n): return (f:=lambda m: int(''.join(map(lambda x:'0111222223'[int(x)], str(m)))))(n+1)-f(n) # _Chai Wah Wu_, Oct 19 2024
%K A136428 sign
%O A136428 0,10
%A A136428 _Reinhard Zumkeller_, Dec 30 2007