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 A080481 #2 Dec 05 2013 19:56:00 %S A080481 0,12,345,6789,1011121314,151617181920,21222324252627, %T A080481 2829303132333435,363738394041424344,45464748495051525354, %U A080481 5556575859606162636465,666768697071727374757677,78798081828384858687888990 %N A080481 Concatenation of next n numbers (a(1) = 0). %C A080481 a(n) is a multiple of 3. %Y A080481 Cf. A080482, A080483, A080484. %K A080481 base,easy,nonn %O A080481 1,2 %A A080481 _Amarnath Murthy_, Mar 11 2003 %E A080481 More terms from Antonio G. Astudillo (afg_astudillo(AT)lycos.com), Apr 06 2003