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 A061514 #3 Dec 05 2013 19:54:51 %S A061514 0,3,6,9,12,45,78,1011,4344,7677,1091010,43124343,76457676, %T A061514 10978109109,4312101143124312,7645434476457645,1097876771097810978, %U A061514 4312101110910104312101143121011,76454344431243437645434476454344 %N A061514 a(0) = 0; a(n) is obtained by incrementing each digit of a(n-1) by 3. %C A061514 In A061511-A061522, A061746-A061750 when the incremented digit exceeds 9 it is written as a 2-digit string. So 9+1 becomes the 2-digit string 10, etc. %K A061514 base,nonn %O A061514 0,2 %A A061514 _Amarnath Murthy_, May 08 2001 %E A061514 More terms from Larry Reeves (larryr(AT)acm.org), May 11 2001