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 A130892 #9 Aug 09 2015 02:03:20
%S A130892 0,1,2,1,4,1,6,1,8,9,10,4,12,4,14,15,16,4,18,4,20,21,22,6,24,25,26,27,
%T A130892 28,6,30,8,32,33,34,35,36,8,38,39,40,10,42,10,44,45,46,10,48,49,50,51,
%U A130892 52,12,54,55,56,57,58,12,60,14,62,63,64,65,66,14,68
%N A130892 a(n) = n if n is not an odd prime number. Otherwise, a(n) = k*ceiling(n/10), where k is the smallest integer such that n < 10^k.
%t A130892 Join[{0,1,2},Table[If[PrimeQ[n],IntegerLength[n]Ceiling[n/10],n],{n,3,99}]] (* _Harvey P. Dale_, Sep 14 2013 *)
%Y A130892 Cf. A131516, A130758, A000027, A001477, A006005.
%K A130892 nonn
%O A130892 1,3
%A A130892 _Mohammad K. Azarian_, Aug 21 2007
%E A130892 Offset corrected by _Mohammad K. Azarian_, Nov 19 2008