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 A244989 #7 Jul 23 2014 10:20:58 %S A244989 0,1,1,2,3,3,3,4,4,5,6,6,6,6,7,8,9,9,9,10,10,11,12,12,13,13,13,13,13, %T A244989 14,15,16,17,18,18,18,18,18,18,19,20,20,20,21,22,23,24,24,24,25,26,26, %U A244989 26,26,27,27,27,27,28,29,29,30,30,31,31,32,33,34,35,35,35,35,36,36,37 %N A244989 Partial sums of A244992: a(1) = 0, and for n >= 1, a(n) = A244992(n) + a(n-1); Inverse function for A244991. %H A244989 Antti Karttunen, <a href="/A244989/b244989.txt">Table of n, a(n) for n = 1..10001</a> %F A244989 a(1) = 0, and for n >= 1, a(n) = A244992(n) + a(n-1). %F A244989 a(n) = n - A244988(n). %F A244989 For all n >= 1, a(A244991(n)) = n. [This works as an inverse function for the injection A244991]. %o A244989 (definec (A244989 n) (if (<= n 1) 0 (+ (A244992 n) (A244989 (-1+ n))))) %Y A244989 Cf. A244988, A244991, A244992, A244321. %K A244989 nonn %O A244989 1,4 %A A244989 _Antti Karttunen_, Jul 22 2014