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 A230407 #7 Nov 13 2013 11:43:14
%S A230407 0,-1,1,3,-5,-1,3,1,3,-5,-1,7,-1,-5,-1,-5,5,5,-5,-11,1,3,-11,1,-3,3,1,
%T A230407 3,-5,-1,7,-1,-5,-1,-5,5,5,-5,-11,1,3,-21,1,-3,-3,9,1,-1,-5,-1,-5,5,5,
%U A230407 -5,-11,1,3,-21,1,-3,-3,-11,-1,-9,-3,5,5,-5,-11,1,3
%N A230407 Absolute value of a(n) tells the size of the n-th side-tree ("tendril", A230430(n)) in the factorial beanstalk; the sign tells on which side of the infinite trunk (A219666) it is.
%C A230407 Positive and negative terms correspond to the tendrils that sprout respectively at the left and right sides of the infinite trunk, when the factorial beanstalk is drawn with the lesser numbers branching to the left. The absolute values give the sizes of those tendrils, with all nodes included: The leaves, the internal vertices as well as the root itself (which is at A230430(n)).
%C A230407 Here a(0) = 0 is a special case, as the infinite trunk starts to grow from its child 1, while the other child is 0 itself. (For both k=0 or k=1 it is true that A219651(k)=0).
%C A230407 This sequence relates to the factorial base representation (A007623) in the same way as A218618 relates to the binary system.
%H A230407 Antti Karttunen, <a href="/A230407/b230407.txt">Table of n, a(n) for n = 0..3149</a>
%F A230407 a(n) = ((-1)^A230430(n)) * A230427(A230430(n)).
%o A230407 (Scheme)
%o A230407 (define (A230407 n) (* (expt -1 (A230430 n)) (A230427 (A230430 n))))
%Y A230407 Partial sums: A230408, A230409.
%K A230407 sign
%O A230407 0,4
%A A230407 _Antti Karttunen_, Nov 10 2013