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 A278164 #10 Nov 16 2016 11:10:31 %S A278164 0,0,1,0,1,2,3,0,1,2,3,4,5,0,1,2,3,4,5,6,7,8,9,0,1,2,3,4,5,6,7,8,9,10, %T A278164 11,12,13,0,1,2,3,4,5,6,7,8,9,10,11,12,13,14,15,16,17,18,19,0,1,2,3,4, %U A278164 5,6,7,8,9,10,11,12,13,14,15,16,17,18,19,20,21,22,23,24,25,0,1,2,3,4,5,6,7,8,9,10,11,12 %N A278164 Irregular triangle read by rows: row n (n >= 0) is obtained by listing numbers 0 .. A000123(n)-1. %H A278164 Antti Karttunen, <a href="/A278164/b278164.txt">Table of n, a(n) for n = 1..9669</a> %F A278164 a(1) = 0; for n > 1, a(n) = n - A131205(A278163(n)) - 1. %e A278164 A000123 -> range -> terms on row n %e A278164 1 [0,0]: 0; %e A278164 2 [0,1]: 0, 1; %e A278164 4 [0,3]: 0, 1, 2, 3; %e A278164 6 [0,5]: 0, 1, 2, 3, 4, 5; %e A278164 10 [0,9]: 0, 1, 2, 3, 4, 5, 6, 7, 8, 9; %e A278164 etc. %o A278164 (Scheme) (define (A278164 n) (if (= 1 n) 0 (- n (A131205 (A278163 n)) 1))) %Y A278164 Obtained by taking the every second row of similar table A277904. %Y A278164 Cf. A000123, A131205, A278163. %K A278164 nonn,tabf %O A278164 1,6 %A A278164 _Antti Karttunen_, Nov 15 2016