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Number of connected components remaining when decimal expansion of the number n is cut from a piece of paper.
4

%I #8 Oct 02 2014 17:53:57

%S 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 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 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 Number of connected components remaining when decimal expansion of the number n is cut from a piece of paper.

%C Assumes that 4 is represented without a hole.

%t 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 Cf. A064529, A064530. Equals A064532 + 1.

%K nonn,easy,base

%O 0,1

%A _N. J. A. Sloane_, Oct 07 2001

%E More terms from _Matthew Conroy_, Oct 09 2001