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.

Showing 1-5 of 5 results.

A127389 Number of fixed points in range [A014137(n-1)..A014138(n-1)] of permutations A127377/A127378 and A127387.

Original entry on oeis.org

1, 1, 0, 1, 2, 4, 10, 23, 56, 138, 344, 870, 2220, 5716, 14828, 38717, 101682, 268416, 711810, 1895432, 5066030, 13586082, 36547534, 98593064, 266661162, 722953814, 1964358938, 5348367006, 14589803090, 39870312218, 109136843138
Offset: 0

Views

Author

Antti Karttunen, Jan 16 2007

Keywords

Crossrefs

This is INVERTi transform of A086625 (appropriately shifted). I.e. INVERT([1, 1, 0, 1, 2, 4, 10, 23, 56, 138, 344, 870, 2220, 5716]) gives: 1, 2, 3, 6, 12, 26, 59, 138, 332, 814, 2028, 5118, ... (beginning of A086625)

Programs

  • PARI
    {a(n)=local(A=1+x+x*O(x^n));for(i=0,n,A=(1 + x*A^2)*(1+x)/(1+x+2*x^2));polcoeff(A,n)}

Formula

G.f. satisfies: A(x) = (1 + x*A(x)^2)*(1+x)/(1+x+2*x^2).

Extensions

Generating function, PARI-program and most of the terms supplied by Paul D. Hanna, Jan 15 2007

A127383 Number of cycles in range [A014137(n-1)..A014138(n-1)] of permutation A127377/A127378.

Original entry on oeis.org

1, 1, 1, 2, 6, 15, 46, 141, 446, 1427, 4722, 15884, 54224, 187380
Offset: 0

Views

Author

Antti Karttunen, Jan 16 2007

Keywords

Crossrefs

A127377 Signature-permutation of a Catalan automorphism, auxiliary bijection for Callan's 2006 bijection on Dyck Paths.

Original entry on oeis.org

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

Views

Author

Antti Karttunen, Jan 16 2007

Keywords

Comments

Used to construct A127379.

Crossrefs

Inverse: A127378. The number of cycles and the number of fixed points in range [A014137(n-1)..A014138(n-1)] of this permutation are given by A127383 and A127389. The maximum cycles and LCM's of cycle sizes begin as 1, 1, 2, 4, 4, 8, 8, 8, 8, 16, 16, 16, 16, 16, ... A127387 shows a variant which is an involution. A127302(a(n)) = A127302(n) holds for all n.

A127380 Signature-permutation of the inverse of Callan's 2006 bijection on Dyck Paths, mirrored version (A057164-conjugate).

Original entry on oeis.org

0, 1, 2, 3, 4, 5, 6, 8, 7, 9, 10, 11, 13, 12, 14, 15, 19, 21, 22, 16, 20, 18, 17, 23, 24, 25, 27, 26, 28, 29, 33, 35, 36, 30, 34, 32, 31, 37, 38, 39, 41, 40, 51, 52, 56, 58, 59, 60, 62, 64, 63, 42, 43, 53, 54, 55, 47, 61, 49, 50, 44, 57, 48, 46, 45, 65, 66, 67, 69, 68, 70, 71
Offset: 0

Views

Author

Antti Karttunen, Jan 16 2007

Keywords

Comments

This automorphism is RIBS-transformation (explained in A122200) of the automorphism A127378 and Callan's original variant A127382 is obtained as A057164(A127380(A057164(n))).

Crossrefs

Inverse: A127379. a(n) = A057164(A127382(A057164(n))). A127302(a(n)) = A127302(n) holds for all n.
Differs from A073288 for the first time at n=49, where a(n)=64, while A073288(49)=63 and differs from A122350 for the first time at n=54, where a(n)=54, while A122350(54)=57.

A127387 Signature-permutation of a Catalan automorphism, a self-inverse variant of A127377.

Original entry on oeis.org

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

Views

Author

Antti Karttunen, Jan 16 2007

Keywords

Comments

Used to construct A127388.

Crossrefs

The number of cycles and the number of fixed points in range [A014137(n-1)..A014138(n-1)] of this involution are given by A127385 and A127389. (This automorphism has the same fixed points as A127377/A127378). A127302(a(n)) = A127302(n) holds for all n.
Showing 1-5 of 5 results.