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 A233270 #14 Jan 03 2014 10:43:32 %S A233270 0,0,-1,0,0,0,1,0,0,2,1,2,0,0,3,3,4,3,4,3,3,0,0,4,4,5,4,6,5,5,3,5,5,6, %T A233270 4,5,4,4,0,0,5,8,9,10,13,13,15,16,17,18,18,17,17,19,19,17,17,18,18,17, %U A233270 16,15,13,13,10,9,8,5,0,0,6,9,14,17,18,20,22,21 %N A233270 a(n) = A233271(n) - A179016(n). %C A233270 For all n>=2, a(1+A213710(n)) = n-2. %C A233270 Except for a(2)=-1 (which seems to be the only negative term in the sequence), the sequences A218600 and A213710 give the positions of zeros. %C A233270 Furthermore, each subrange [A213710(n)..A218600(n+1)] is palindromic. A233268 gives the middle points of those ranges, the sequence A234018 gives the values at those points, while A234019 gives the maximum term in that range in this sequence. %H A233270 Antti Karttunen, <a href="/A233270/b233270.txt">Rows 0..16, flattened</a> %F A233270 a(n) = A233271(n) - A179016(n). %F A233270 a(A218602(n)) = a(n). [This is just a claim that each row is palindrome] %e A233270 This irregular table begins as: %e A233270 0; %e A233270 0; %e A233270 -1; %e A233270 0, 0; %e A233270 0, 1, 0; %e A233270 0, 2, 1, 2, 0; %e A233270 0, 3, 3, 4, 3, 4, 3, 3, 0; %e A233270 0, 4, 4, 5, 4, 6, 5, 5, 3, 5, 5, 6, 4, 5, 4, 4, 0; %e A233270 ... %e A233270 After zero, each row n is A213709(n-1) elements long. %o A233270 (Scheme) %o A233270 (define (A233270 n) (- (A233271 n) (A179016 n))) %Y A233270 Except for a(2)=-1 (which seems to be the only negative term in the sequence), the sequences A218600 and A213710 give the positions of zeros. %Y A233270 Cf. A080468, A179016, A233271, A233268, A233274, A234018, A234019, A234020. %K A233270 sign,tabf %O A233270 0,10 %A A233270 _Antti Karttunen_, Dec 14 2013