cp's OEIS Frontend

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.

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A218787 a(n) = A014486-index for the n-th tendril of infinite beanstalk (A213730(n)), with the "lesser numbers to the left side" construction.

Original entry on oeis.org

0, 0, 0, 0, 1, 0, 0, 1, 2, 0, 0, 0, 1, 2, 0, 8, 0, 0, 1, 0, 0, 1, 2, 0, 8, 0, 0, 1, 8, 0, 0, 3, 0, 2, 1, 0, 0, 0, 1, 2, 0, 8, 0, 0, 1, 8, 0, 0, 3, 0, 2, 1, 0, 8, 0, 0, 3, 0, 60, 0, 0, 172, 0, 2, 0, 1, 0, 0, 1, 2, 0, 8, 0, 0, 1, 8, 0, 0, 3, 0, 2, 1, 0, 8, 0, 0
Offset: 1

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Author

Antti Karttunen, Nov 11 2012

Keywords

Comments

"Tendrils" of the beanstalk are the finite side-trees sprouting from its infinite trunk (see A179016) at the numbers given by A213730.

Examples

			A213730(9)=22, and from that branches 24 and 25 (as both A011371(24)=A011371(25)=22) and while 24 is a leaf (in A055938) the other branch 25 further branches to two leaves (as both A011371(28)=A011371(29)=25).
When we construct a binary tree from this in such a fashion that the lesser numbers go to the left, we obtain:
...........
...28...29.
.....\./...
..24..25...
...\ /.....
....22.....
...........
and the binary tree
........
...\./..
....*...
.\./....
..*.....
........
is located as A014486(2) in the normal encoding order of binary trees, thus a(9)=2.
		

Crossrefs

These are the mirror-images of binary trees given in A218788, i.e. a(n) = A057163(A218788(n)). A218786 gives the sizes of these trees. Cf. A072764, A218609, A218611.

A218611 Positions in A218787 and A218788 of successive distinct values.

Original entry on oeis.org

1, 5, 9, 16, 32, 59, 62, 115, 118, 208, 212, 213, 384, 389, 649, 654, 686, 703, 708, 716, 720, 723, 1310, 1326, 1328, 1338, 2236, 2369, 2422, 2432, 2452, 2458, 2466, 2476, 2486, 2488, 4545, 4601, 4625, 4627, 4637, 7811, 7817, 7819, 7826, 8287, 8511, 8526, 8631
Offset: 1

Views

Author

Antti Karttunen, Nov 11 2012

Keywords

Comments

The terms give the positions to A213730 where for the first time a new, never-before-encountered sidetree ("tendril") appears from the side of the infinite beanstalk. See A179016, A218609 and also A218612.

Crossrefs

A218610 Distinct values of A218788 in the order of appearance.

Original entry on oeis.org

0, 1, 3, 4, 2, 37, 110, 18, 11, 32, 33, 4755, 16127, 73542063, 97105360, 62, 1306632183, 39288694215537689, 193, 8150, 719, 12, 5, 13505, 246941338376004599, 13, 45, 407, 944077158106260984, 4975012595, 5738426278308884, 26, 27439590092251146768825651348524279
Offset: 1

Views

Author

Antti Karttunen, Nov 11 2012

Keywords

Comments

a(n) = A014486-index for the n-th tendril of the infinite beanstalk (A179016), which has not been encountered before, constructed with lesser numbers coming to the right, and larger to the left hand side of each branch.

Crossrefs

These are the mirror-images of binary trees given in A218609, i.e. a(n) = A057163(A218609(n)). A218613 gives the sizes of these trees. Cf. A218611.

Programs

Formula

a(n) = A218788(A218611(n)).
Showing 1-3 of 3 results.