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 A276438 #7 Sep 04 2016 17:20:31 %S A276438 1,1,1,-1,1,1,1,-1,1,-1,1,-1,1,-1,1,-1,1,1,1,-1,1,-1,-1,2,1,-1,-1,2,1, %T A276438 -1,1,-1,-1,2,1,-1,-1,-1,1,-1,2,1,-1,-1,2,1,-1,-1,-1,-1,1,-1,1,-1,1, %U A276438 -1,1,1,1,-1,1,-1,-1,2,1,-1,-1,-1,1,-1,1,1,1,-1,-1,-1,1,-1,2,1,-1,1,-1,-1,-1,1,1,1,-1,1,1,1,-1 %N A276438 a(n) = (A274647(n)-A274647(n-1)) / n. %C A276438 a(n) tells what k was finally used when determining the value of A274647(n), with minus sign if subtraction was chosen and with positive sign if addition was chosen. %C A276438 First 1 occurs at n=1, first 2 at n=24, first 3 at n=128, first 4 at n=204, first 5 at n=17903, first 6 at n=210027. %C A276438 First -1 occurs at n=4, first -2 at n=124, first -3 at n=5882. %H A276438 Antti Karttunen, <a href="/A276438/b276438.txt">Table of n, a(n) for n = 1..17903</a> %F A276438 a(n) = (A274647(n)-A274647(n-1)) / n. %o A276438 (Scheme) (define (A276438 n) (/ (- (A274647 n) (A274647 (- n 1))) n)) %Y A276438 Cf. A274647. %Y A276438 Cf. A276439 (partial sums). %K A276438 sign %O A276438 1,24 %A A276438 _Antti Karttunen_, Sep 04 2016