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 A064531 #8 Oct 02 2014 17:53:57
%S A064531 2,1,1,1,1,1,2,1,3,2,2,1,1,1,1,1,2,1,3,2,2,1,1,1,1,1,2,1,3,2,2,1,1,1,
%T A064531 1,1,2,1,3,2,2,1,1,1,1,1,2,1,3,2,2,1,1,1,1,1,2,1,3,2,3,2,2,2,2,2,3,2,
%U A064531 4,3,2,1,1,1,1,1,2,1,3,2,4,3,3,3,3,3,4,3,5,4,3,2,2,2,2,2,3,2,4,3,3,2,2,2,2
%N A064531 Number of connected components remaining when decimal expansion of the number n is cut from a piece of paper.
%C A064531 Assumes that 4 is represented without a hole.
%t A064531 a[n_ /; 0 <= n <= 9] := a[n] = {2, 1, 1, 1, 1, 1, 2, 1, 3, 2}[[n + 1]]; a[n_] := Total[a /@ (id = IntegerDigits[n])] - Length[id] + 1 ; Table[a[n], {n, 0, 104}] (* _Jean-François Alcover_, Nov 22 2013 *)
%Y A064531 Cf. A064529, A064530. Equals A064532 + 1.
%K A064531 nonn,easy,base
%O A064531 0,1
%A A064531 _N. J. A. Sloane_, Oct 07 2001
%E A064531 More terms from _Matthew Conroy_, Oct 09 2001