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 A075005 #5 Dec 05 2013 19:55:34 %S A075005 802,1080,1358,1635,1913,2191,2469,2746,27774,302777,3280277,3532802, %T A075005 3785328,4037853,4290378,4542903,4795429,5047954,5300479,5553004, %U A075005 5805530,6058055,6310580,6563105,6815631,7068156,7320681,7573206 %N A075005 Floor[ concatenation of n+3, n+2, n+1 and n divided by 4 ]. %p A075005 seq(floor(((n+3)*1000+(n+2)*100+(n+1)*10+n)/4), n=0..7), floor(111098/4), floor(1211109/4), seq(floor(((n+3)*1000^2+(n+2)*100^2+(n+1)*10^2+n)/4), n=10..99); %Y A075005 Cf. A074991 to A075000, A075003, A075004 and A074996 to A075010. %K A075005 base,nonn %O A075005 0,1 %A A075005 _Amarnath Murthy_, Sep 01 2002 %E A075005 More terms from _Sascha Kurz_, Jan 14 2003