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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A080270 Positions of A080268 in A014486.

Original entry on oeis.org

1, 8, 62, 6213, 72665, 11517948
Offset: 0

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Author

Antti Karttunen, Mar 02 2003

Keywords

Crossrefs

a(n) = A080300(A080268(n)). Cf. A080271.

Formula

a(n) = A057118(A080265(n)).

A082859 Lower triangular region of A082858.

Original entry on oeis.org

0, 0, 1, 0, 1, 2, 0, 1, 1, 3, 0, 1, 2, 1, 4, 0, 1, 2, 1, 2, 5, 0, 1, 2, 3, 2, 2, 6, 0, 1, 1, 3, 1, 1, 3, 7, 0, 1, 1, 3, 1, 1, 3, 3, 8, 0, 1, 2, 1, 4, 2, 2, 1, 1, 9, 0, 1, 2, 1, 4, 2, 2, 1, 1, 4, 10, 0, 1, 2, 1, 4, 5, 2, 1, 1, 4, 4, 11, 0, 1, 2, 1, 2, 5, 2, 1, 1, 2, 2, 5, 12, 0, 1, 2, 1, 2, 5, 2, 1, 1, 2, 2, 5, 5, 13, 0, 1, 2, 3, 4, 2, 6, 3, 3, 4, 4, 4, 2, 2, 14
Offset: 0

Views

Author

Antti Karttunen, May 06 2003

Keywords

Crossrefs

A082861 Lower triangular region of A082860.

Original entry on oeis.org

0, 1, 1, 2, 2, 2, 3, 3, 6, 3, 4, 4, 4, 14, 4, 5, 5, 5, 15, 11, 5, 6, 6, 6, 6, 14, 15, 6, 7, 7, 16, 7, 42, 43, 16, 7, 8, 8, 19, 8, 51, 52, 19, 20, 8, 9, 9, 9, 37, 9, 28, 37, 121, 149, 9, 10, 10, 10, 38, 10, 29, 38, 122, 150, 25, 10, 11, 11, 11, 39, 11, 11, 39, 123, 151, 28, 29, 11, 12, 12, 12, 40, 30, 12, 40, 124, 152, 84, 85, 30, 12, 13, 13, 13, 41, 33, 13, 41, 125, 153
Offset: 0

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Author

Antti Karttunen, May 06 2003

Keywords

Crossrefs

A083938 A014486-indices of binary trees whose left and right subtree are identical.

Original entry on oeis.org

0, 1, 6, 42, 52, 385, 414, 477, 506, 555, 4089, 4180, 4388, 4479, 4645, 5095, 5186, 5394, 5485, 5651, 5969, 6060, 6226, 6502, 47363, 47661, 48366, 48664, 49237, 50800, 51098, 51803, 52101, 52674, 53808, 54106, 54679, 55681, 59311, 59609, 60314
Offset: 0

Views

Author

Antti Karttunen, May 13 2003

Keywords

Comments

Fixed points of permutation A069770. Diagonal of A072764 (and A072766).

Crossrefs

a(n) = A080300(A083939(n)). Cf. A083940.

Formula

a(0)=0, a(n)=A072764bi(n-1, n-1).

A083940 A014486-indices of symmetric binary trees.

Original entry on oeis.org

0, 1, 6, 43, 51, 389, 416, 477, 504, 551, 4102, 4191, 4397, 4485, 4649, 5100, 5187, 5393, 5481, 5645, 5964, 6051, 6215, 6489, 47404, 47700, 48403, 48697, 49268, 50833, 51126, 51828, 52120, 52691, 53829, 54120, 54690, 55690, 59334, 59627, 60328
Offset: 0

Views

Author

Antti Karttunen, May 13 2003

Keywords

Comments

Fixed points of permutation A057163.

Crossrefs

a(n) = A080300(A083941(n)). Cf. A083938, A084108.

Formula

a(0)=0, a(n)=A072764bi(n-1, A057163(n-1)).

A085200 Inverse function of N -> N injection A071155.

Original entry on oeis.org

0, 1, 0, 2, 0, 3, 0, 0, 0, 4, 0, 6, 0, 0, 0, 5, 0, 7, 0, 0, 0, 0, 0, 8, 0, 0, 0, 0, 0, 0, 0, 0, 0, 9, 0, 14, 0, 0, 0, 11, 0, 16, 0, 0, 0, 0, 0, 19, 0, 0, 0, 0, 0, 0, 0, 0, 0, 10, 0, 15, 0, 0, 0, 12, 0, 17, 0, 0, 0, 0, 0, 20, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 13, 0, 18, 0, 0, 0, 0, 0, 21, 0, 0, 0
Offset: 0

Views

Author

Antti Karttunen, Jun 23 2003

Keywords

Comments

a(0)=0 because A071155(0)=0, but a(n) = 0 also for those n which do not occur as values of A071155. All positive natural numbers occur here once.

Crossrefs

a(A071155(n)) = n for all n. Cf. A080300.

A126310 A014486-index for the Dyck path "derived" from the n-th Dyck path encoded by A014486(n).

Original entry on oeis.org

0, 0, 1, 0, 2, 1, 1, 1, 0, 4, 2, 2, 2, 1, 2, 1, 2, 3, 1, 1, 1, 1, 0, 9, 4, 4, 4, 2, 4, 2, 4, 5, 2, 2, 2, 2, 1, 4, 2, 2, 2, 1, 4, 2, 6, 7, 3, 2, 2, 3, 1, 2, 1, 2, 3, 1, 2, 3, 3, 1, 1, 1, 1, 1, 0, 23, 9, 9, 9, 4, 9, 4, 9, 10, 4, 4, 4, 4, 2, 9, 4, 4, 4, 2, 9, 4, 11, 12, 5, 4, 4, 5, 2, 4, 2, 4, 5, 2, 4, 5, 5
Offset: 0

Views

Author

Antti Karttunen, Jan 02 2007

Keywords

Comments

According to Vaillé, the concept of "dérivation des ponts" is defined by Kreweras, in "Sur les éventails de segments" paper.

Crossrefs

Formula

a(n) = A125986(A126309(A125985(n))).

A209643 A014486-indices for rooted plane trees where non-leaf branching can occur only at the leftmost branch of any level, but nowhere else.

Original entry on oeis.org

0, 1, 2, 3, 4, 6, 7, 8, 9, 14, 16, 17, 19, 20, 21, 22, 23, 37, 42, 44, 45, 51, 53, 54, 56, 57, 58, 60, 61, 62, 63, 64, 65, 107, 121, 126, 128, 129, 149, 154, 156, 157, 163, 165, 166, 168, 169, 170, 177, 179, 180, 182, 183, 184, 186, 187, 188, 189, 191, 192, 193, 194, 195, 196, 197, 329, 371, 385, 390, 392, 393, 461, 475, 480, 482
Offset: 0

Views

Author

Antti Karttunen, Mar 24 2012

Keywords

Comments

5 is not member of this sequence, as it encodes in A014486 a general tree:
..|
\/
which has a nonempty branch which is not the leftmost child of its parent vertex.

Crossrefs

Formula

a(n) = A080300(A209641(n)).

A083934 A014486-indices of A083932-trees.

Original entry on oeis.org

0, 3, 15, 22, 113, 120, 178, 185, 196, 1103, 1110, 1168, 1175, 1186, 1787, 1794, 1852, 1859, 1870, 2022, 2029, 2040, 2055, 12257, 12264, 12322, 12329, 12340, 12941, 12948, 13006, 13013, 13024, 13176, 13183, 13194, 13209, 20122, 20129, 20187
Offset: 0

Views

Author

Antti Karttunen, May 13 2003

Keywords

Crossrefs

Inverse function: A083935.

Formula

a(n) = A080300(A083932(n)).

A083942 Positions of breadth-first-wise encodings (A002542) of the complete binary trees (A084107) in A014486.

Original entry on oeis.org

0, 1, 8, 625, 13402696, 19720133460129649, 126747521841153485025455279433135688, 15141471069096667541622192498608408980462133134430650704600552060872705905
Offset: 0

Views

Author

Antti Karttunen, May 13 2003

Keywords

Crossrefs

Cf. A014138 (partial sums of Catalan numbers), A000108 (Catalan Numbers).

Formula

a(n) = A057118(A084108(n)).
a(n) = A080300(A002542(n)) [provided that 2^((2^n)-1)*((2^((2^n)-1))-1) is indeed the formula for A002542].
Conjecture: a(n) = A014138(2^n-2) for n>0. - Alexander Adamchuk, Nov 10 2007
Conjecture: a(n) = Sum_{k=1..2^n-1} A000108(k). - Alexander Adamchuk, Nov 10 2007
Let h(n) = -((C(2*n,n)*hypergeom([1,1/2+n],[2+n],4))/(1+n)+I*sqrt(3)/2+1/2). Assuming Adamchuk's conjecture a(n) = h(2^n) and A014138(n) = h(n+1). - Peter Luschny, Mar 09 2015
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