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 A155538 #4 Mar 30 2012 16:51:14 %S A155538 115792089237316195423570985008687907853269984665640564039457584007913129639936, %T A155538 340282366920938463463374607431768211456,18446744073709551616, %U A155538 4294967296,65536,256,16,4,2,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1 %N A155538 Take square root of previous term. %Y A155538 A001146 read backwards. %K A155538 nonn %O A155538 1,1 %A A155538 b5142(AT)hotmail.com, Jan 23 2009 %E A155538 Edited with the addition of 4 leading terms. - _N. J. A. Sloane_, Jan 24 2009