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 A157140 #11 Mar 30 2012 18:52:03 %S A157140 9,19,19,47,47,47,47,98,98,98,98,98,98,98,98,220,220,220,220,220,220, %T A157140 220,220,220,220,220,220,220,220,220,220,441,441,441,441,441,441,441, %U A157140 441,441,441,441,441,441,441,441,441,441,441,441,441,441,441,441,441 %N A157140 A091411(k+3) replicated 2^k times, k= 0, 1, 2, 3, ... %C A157140 Generated from the quadrisection b(n) = 4, 13, 23, 32, 51, 60, 70, 79, 102, 111, 121, 130,... of A156799 as follows: %C A157140 1) b(n+1)-b(n) = 9, 10, 9, 19, 9, 10, 9, 23, 9, 10, 9, 19,.., %C A157140 2) b(n+2)-b(n) = 19, 19, 28, 28, 19, 19, 32, 32, 19, 19, 28, 28,..., %C A157140 3) b(n+4)-b(n) = 47, 47, 47, 47, 51, 51, 51, 51, 47, 47, 47, 47,..., %C A157140 4) b(n+8)-b(n) = 98, 98, 98, 98, 98, 98, 98, 98, 122, 122, 122, 122, 122, 122, 122, 122, 98, .. . %C A157140 The sum of neighbors at the first jump of b(n+2^k) is 9+10 = 19 (k=0), 19+28 = 47 (k=1), 47+51 = 98 (k=2), 98+122 = 220 (k=3), and in general A091411(k+3). %K A157140 nonn %O A157140 0,1 %A A157140 _Paul Curtz_, Feb 24 2009