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 A218618 Absolute value of a(n) tells the size of the n-th side-tree ("tendril", A213730(n)) in the binary beanstalk; the sign tells on which side of the infinite trunk (A179016) it is. 4
 0, 1, -1, 1, -1, 3, 1, -1, 3, 5, -1, 1, -1, 3, 5, -1, -7, 1, 1, 3, 1, -1, 3, 5, -1, -7, 1, 1, 3, -7, 1, 1, -5, 1, -5, -3, -1, 1, -1, 3, 5, -1, -7, 1, 1, 3, -7, 1, 1, -5, 1, -5, -3, -1, -7, 1, 1, -5, 1, 11, 1, 1, 13, 1, -5, -1, 3, 1, -1, 3, 5, -1, -7, 1, 1, 3 (list; graph; refs; listen; history; text; internal format)
 OFFSET 0,6 COMMENTS Positive and negative terms correspond to the tendrils that sprout respectively at the left and right sides of the infinite trunk, when the 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: A213730(n). LINKS Antti Karttunen, Table of n, a(n) for n = 0..8727 FORMULA a(n) = -1^A213730(n) * A213727(A213730(n)). PROG (Scheme): (define (A218618 n) (* (expt -1 (A213730 n)) (A213727 (A213730 n)))) CROSSREFS Partial sums: A218785, A218789. Cf. also A218786, A218613. Sequence in context: A319182 A247282 A246685 * A271451 A131248 A116445 Adjacent sequences:  A218615 A218616 A218617 * A218619 A218620 A218621 KEYWORD sign AUTHOR Antti Karttunen, Dec 03 2012 STATUS approved

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Last modified October 17 03:43 EDT 2018. Contains 316275 sequences. (Running on oeis4.)