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.

Previous Showing 11-18 of 18 results.

A074681 Permutation of natural numbers induced by the Catalan bijection gmA074681! acting on the parenthesizations encoded by A014486/A063171.

Original entry on oeis.org

0, 1, 3, 2, 6, 8, 7, 5, 4, 15, 14, 19, 20, 22, 16, 21, 18, 11, 13, 17, 12, 10, 9, 39, 41, 40, 38, 37, 52, 51, 53, 55, 54, 60, 61, 62, 64, 43, 42, 56, 57, 63, 47, 59, 48, 29, 28, 50, 33, 34, 36, 44, 58, 49, 30, 35, 46, 32, 25, 27, 45, 31, 26, 24, 23, 113, 112, 117, 118, 120
Offset: 0

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Author

Antti Karttunen, Sep 11 2002

Keywords

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Crossrefs

Inverse of A074682. a(n) = A057163(A074684(A057163(n))). Cf. A074685, A074687, A074689. Occurs in A073200 as row 5572432.

A085159 Permutation of natural numbers induced by the Catalan bijection gma085159 acting on symbolless S-expressions encoded by A014486/A063171.

Original entry on oeis.org

0, 1, 2, 3, 4, 6, 7, 5, 8, 9, 11, 14, 16, 19, 17, 20, 12, 10, 13, 21, 15, 18, 22, 23, 25, 28, 30, 33, 37, 39, 42, 44, 47, 51, 53, 56, 60, 45, 48, 54, 57, 61, 31, 34, 26, 24, 27, 35, 29, 32, 36, 58, 62, 40, 38, 41, 49, 43, 46, 50, 63, 52, 55, 59, 64, 65, 67, 70, 72, 75
Offset: 0

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Author

Antti Karttunen, Jun 23 2003

Keywords

Comments

This Catalan bijection rotates the interpretations (pp)-(rr) of Stanley, using the "rising slope" mapping illustrated in A085161.

Links

Crossrefs

Inverse: A085160. a(n) = A085161(A085160(A085161(n))) = A085169(A082315(A085170(n))) = A074684(A082315(A074683(n))) = A085173(A085173(n)). Occurs in A073200. Cf. also A085165-A085168, A086429. Scheme-function app-to-xrt given in A085203.
Number of cycles: A054357. Number of fixed points: A046698. (In range [A014137(n-1)..A014138(n-1)] of this permutation, possibly shifted one term left or right).

A085160 Permutation of natural numbers induced by the Catalan bijection gma085160 acting on symbolless S-expressions encoded by A014486/A063171.

Original entry on oeis.org

0, 1, 2, 3, 4, 7, 5, 6, 8, 9, 17, 10, 16, 18, 11, 20, 12, 14, 21, 13, 15, 19, 22, 23, 45, 24, 44, 46, 25, 48, 26, 42, 49, 27, 43, 47, 50, 28, 54, 29, 53, 55, 30, 57, 31, 37, 58, 32, 38, 56, 59, 33, 61, 34, 39, 62, 35, 40, 51, 63, 36, 41, 52, 60, 64, 65, 129, 66, 128, 130
Offset: 0

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Author

Antti Karttunen, Jun 23 2003

Keywords

Comments

This Catalan bijection rotates the interpretations (pp)-(rr) of Stanley, using the "rising slope" mapping illustrated in A085161.

Links

Crossrefs

Inverse: A085159. a(n) = A085161(A085159(A085161(n))) = A085169(A082316(A085170(n))) = A074684(A082316(A074683(n))) = A085174(A085174(n)). Occurs in A073200. Cf. also A085165-A085168, A086430.
Number of cycles: A054357. Number of fixed points: A046698. (In range [A014137(n-1)..A014138(n-1)] of this permutation, possibly shifted one term left or right).

A085184 Sequence A085183 shown in base 4. Quaternary code for binary trees.

Original entry on oeis.org

0, 1, 2, 11, 12, 21, 22, 30, 111, 112, 121, 122, 130, 211, 212, 221, 222, 230, 301, 302, 310, 320, 1111, 1112, 1121, 1122, 1130, 1211, 1212, 1221, 1222, 1230, 1301, 1302, 1310, 1320, 2111, 2112, 2121, 2122, 2130, 2211, 2212, 2221, 2222, 2230, 2301, 2302
Offset: 1

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Author

Antti Karttunen, Jun 14 2003

Keywords

Comments

This sequence gives two alternative ways to encode rooted plane binary trees (Stanley's interpretation 'c' = interpretation 'd' without the outermost edges):
A: scan each term from left to right and for each 0, add a leaf node to the tree (terminate a branch), for each 1, add a leftward leaning branch \, for each 2, add a rightward leaning branch / and for each 3, add a double-branch \/ and continue in left-to-right, depth-first fashion.
B: Like method A, but the roles of digits 1 and 2 are swapped. When one compares the generated trees to the "standard order" as specified in the illustrations for A014486, one obtains the permutation A074684/A074683 for the case A and A082356/A082355 for the case B.
If we assign the following weights for each digit: w(0) = -1, w(1) = w(2) = 0, w(3) = +1, then the sequence gives all base-4 numbers for which all the partial sums of digit weights (from the most significant to the least significant end) are nonnegative and the final sum is zero. The initial term 0 is considered to have no significant digits at all, so its total weight is zero also.

Examples

			For the first eleven terms the following binary trees are constructed with method A. With method B we would get their mirror images, although this doesn't hold in general (e.g. for terms like 301-320).
........................................................\......./......\...
.....................\......./.......\......./...........\......\....../...
..*......\....../.....\......\......./....../.....\/......\......\.....\...
..0......1......2.....11.....12.....21.....22.....30....111....112....121..

Links

Crossrefs

Cf. A085185. Number of terms with n significant digits is given by A000108(n+1).

Formula

a(n) = A007090(A085183(n)).

A086425 Permutation of natural numbers induced by the Catalan bijection gma086425 acting on symbolless S-expressions encoded by A014486/A063171.

Original entry on oeis.org

0, 1, 3, 2, 8, 7, 6, 4, 5, 22, 21, 20, 17, 18, 19, 16, 14, 9, 11, 15, 10, 13, 12, 64, 63, 62, 58, 59, 61, 57, 54, 45, 48, 55, 46, 50, 49, 60, 56, 53, 44, 47, 51, 42, 37, 23, 28, 39, 25, 33, 30, 52, 43, 38, 24, 29, 41, 27, 36, 35, 40, 26, 34, 31, 32, 196, 195, 194, 189, 190
Offset: 0

Views

Author

Antti Karttunen, Jun 23 2003

Keywords

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Crossrefs

Inverse: A086426. a(n) = A057164(A074684(n)). Occurs in A073200. Cf. also A086427, A086428, A086429, A086430, A086431.

A085173 Permutation of natural numbers induced by the Catalan bijection gma085173 acting on symbolless S-expressions encoded by A014486/A063171.

Original entry on oeis.org

0, 1, 3, 2, 8, 7, 5, 6, 4, 22, 21, 18, 20, 17, 13, 12, 15, 19, 14, 10, 16, 11, 9, 64, 63, 59, 62, 58, 50, 49, 55, 61, 54, 46, 57, 48, 45, 36, 35, 32, 34, 31, 41, 40, 52, 60, 51, 38, 56, 39, 37, 27, 26, 43, 47, 42, 29, 53, 33, 28, 24, 44, 30, 25, 23, 196, 195, 190, 194, 189
Offset: 0

Views

Author

Antti Karttunen, Jun 23 2003

Keywords

Comments

This Catalan bijection rotates by "half step" the interpretations (pp)-(rr) of Stanley, using the "rising slope" mapping illustrated in A085161.

Links

Crossrefs

Inverse: A085174. a(n) = A085161(A085174(A085161(n))) = A085169(A057501(A085170(n))) = A074684(A057501(A074683(n))). Occurs in A073200. Cf. also A085159 (whole step rotate), A086427.
Number of cycles: A002995. Number of fixed points: A019590. Max. cycle size: A057543. (In range [A014137(n-1)..A014138(n-1)] of this permutation, possibly shifted one term left or right).

A085174 Permutation of natural numbers induced by the Catalan bijection gma085174 acting on symbolless S-expressions encoded by A014486/A063171.

Original entry on oeis.org

0, 1, 3, 2, 8, 6, 7, 5, 4, 22, 19, 21, 15, 14, 18, 16, 20, 13, 11, 17, 12, 10, 9, 64, 60, 63, 52, 51, 59, 56, 62, 41, 39, 58, 40, 38, 37, 50, 47, 49, 43, 42, 55, 53, 61, 36, 33, 54, 35, 29, 28, 46, 44, 57, 32, 30, 48, 34, 27, 25, 45, 31, 26, 24, 23, 196, 191, 195, 178, 177
Offset: 0

Views

Author

Antti Karttunen, Jun 23 2003

Keywords

Comments

This Catalan bijection rotates by "half step" the interpretations (pp)-(rr) of Stanley, using the "rising slope" mapping illustrated in A085161.

Links

Crossrefs

Inverse: A085173. a(n) = A085161(A085173(A085161(n))) = A085169(A057502(A085170(n))) = A074684(A057502(A074683(n))). Occurs in A073200. Cf. also A085160 (whole step rotate), A086428.
Number of cycles: A002995. Number of fixed points: A019590. Max. cycle size: A057543. (In range [A014137(n-1)..A014138(n-1)] of this permutation, possibly shifted one term left or right).

A125981 Signature-permutation of Deutsch's 2000 bijection on ordered trees.

Original entry on oeis.org

0, 1, 3, 2, 7, 8, 5, 6, 4, 17, 18, 20, 22, 21, 12, 13, 15, 16, 19, 10, 11, 14, 9, 45, 46, 48, 50, 49, 54, 55, 61, 63, 64, 57, 59, 62, 58, 31, 32, 34, 36, 35, 40, 41, 43, 44, 47, 52, 53, 60, 56, 26, 27, 29, 30, 33, 38, 39, 42, 51, 24, 25, 28, 37, 23, 129, 130, 132, 134, 133
Offset: 0

Views

Author

Antti Karttunen, Jan 02 2007

Keywords

Comments

Deutsch shows in his 2000 paper that this automorphism converts any ordered tree with the number of nodes having degree q to a tree with an equal number of odd-level nodes having degree q-1, from which it follows that, for each positive integer q, the parameters "number of nodes of degree q" and "number of odd-level nodes of degree q-1" are equidistributed. He also shows that this automorphism converts any tree with k leaves to a tree with k even-level nodes, i.e., in OEIS terms, A057514(n) = A126305(A125981(n)).
To obtain the signature permutation, we apply the given Scheme-function *A125981 to the parenthesizations as encoded and ordered by A014486/A063171 (and surrounded by extra pair of parentheses to make a valid Scheme-list) and for each n, we record the position of the resulting parenthesization (after discarding the outermost parentheses from the Scheme-list) in A014486/A063171 and this value will be a(n).

Links

Crossrefs

Inverse: A125982. The number of cycles, maximum cycle sizes and LCM's of all cycle sizes in range [A014137(n-1)..A014138(n-1)] of this permutation seem to be given by A089411, A086586 and A089412, thus this is probably a conjugate of A074683/A074684. A125983 gives the A057163-conjugate.
Previous Showing 11-18 of 18 results.

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