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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A057547 A014486-encodings of Catalan mountain ranges with no sea-level valleys, i.e., the rooted plane general trees with root degree = 1.

Original entry on oeis.org

2, 12, 52, 56, 212, 216, 228, 232, 240, 852, 856, 868, 872, 880, 916, 920, 932, 936, 944, 964, 968, 976, 992, 3412, 3416, 3428, 3432, 3440, 3476, 3480, 3492, 3496, 3504, 3524, 3528, 3536, 3552, 3668, 3672, 3684, 3688, 3696, 3732, 3736, 3748, 3752, 3760
Offset: 0

Views

Author

Antti Karttunen Sep 07 2000

Keywords

Comments

This one-to-one correspondence between all rooted plane trees and one node larger, root degree = 1 trees illustrates the fact that INVERT(A000108) = LEFT(A000108). (Catalan numbers shift left under Cameron's A transformation.)
From Ruud H.G. van Tol, May 13 2024: (Start)
Sequence on a lattice:
Tree Paths Decimal Count
|_ 10 2 1
|. 1100 12 1
||._ 110100 -111000 52,56 2
|||_._ 11010100 -11110000 212-240 5
|||_|. 1101010100-1111100000 852-992 14
... (End)

Crossrefs

Double-trunked trees: A057517. Cf. also A057548, A057549.

Programs

  • Maple
    alltrees2singletrunked := n -> pars2binexp([binexp2pars(n)]); # Just surround with extra parentheses.
  • PARI
    a_rows(N) = my(a=Vec([[2]], N)); for(r=1, N-1, my(b=a[r], c=List()); foreach(b, t, for(i=1, valuation(t, 2), listput(~c, (t<<2)+(2<Ruud H.G. van Tol, May 25 2024

Formula

a(n) = A014486(A057548(n)) and also from n > 0 onward = A079946(A014486(n)).
a(n) = alltrees2singletrunked(A014486[n]) (see Maple code below and in A057501).

A075164 Position of A014486(n-1) in A075165.

Original entry on oeis.org

1, 2, 3, 4, 5, 6, 9, 8, 16, 7, 10, 15, 12, 24, 25, 18, 27, 32, 64, 81, 512, 256, 65536, 11, 14, 21, 20, 40, 35, 30, 45, 48, 96, 135, 768, 384, 98304, 49, 50, 75, 36, 72, 125, 54, 243, 128, 1024, 729, 32768, 4096, 16777216, 625, 162, 19683, 33554432, 262144
Offset: 1

Views

Author

Antti Karttunen, Sep 13 2002

Keywords

Comments

See A075166.

Crossrefs

Inverse of A075163. a(n) = A075162(n-1)+1.

Formula

a(n) = A106443(A106454(n)). A000040(n) = a(1+A014137(n)). The powers of two are located at indices given by A057548 + 1, permuted by this same sequence, i.e. a(A057548(n)+1) = A000079(a(n)). - Antti Karttunen, May 09 2005

A085205 Array A(x,y): induced by the 2-ary form of the list-function 'list' present in the programming languages Lisp and Scheme, in the same way as A085201 is induced by the 2-ary 'append'-function. Listed antidiagonalwise as A(0,0), A(1,0), A(0,1), A(2,0), A(1,1), A(0,2), ...

Original entry on oeis.org

2, 6, 5, 16, 15, 12, 19, 43, 40, 13, 44, 52, 124, 41, 31, 47, 127, 152, 125, 115, 32, 53, 136, 388, 153, 379, 116, 34, 56, 155, 416, 389, 469, 380, 118, 35, 60, 164, 478, 417, 1237, 470, 382, 119, 36, 128, 178, 506, 479, 1327, 1238, 472, 383, 120, 87, 131, 391
Offset: 0

Views

Author

Antti Karttunen, Jun 23 2003

Keywords

Crossrefs

Transpose: A085206. Row 0: A085226, Column 0: A085227, Diagonal: A085228.

Formula

a(x, y) = A072764bi(x, A057548(y)).

A376402 Bitwise XOR (centrally aligned) of two consecutive terms of A122242.

Original entry on oeis.org

164, 628, 2444, 10040, 34424, 142400, 612536, 2536016, 8772720, 36320296, 156298040, 648930320, 2246427920, 9290072680, 40123676576, 166398412640, 574717970240, 2376856817864, 10244120543704, 42544644116352, 146496800436256, 607708669110320, 2625008220416552, 10882360875506928, 37586414897168848, 156056124134144296
Offset: 1

Views

Author

Antti Karttunen, Sep 22 2024

Keywords

Crossrefs

Programs

Formula

a(n) = A122242(1+n) XOR 2*A122242(n).

A376412 a(n) = A122242(4+n) XOR 16*A122242(n).

Original entry on oeis.org

14544, 64920, 258096, 925720, 3703264, 16562224, 66158664, 237396008, 948568384, 4239130768, 16949182920, 60767078320, 243080890624, 1085016114240, 4341071150792, 15535530051144, 62225888982288, 277421534227968, 1111070191401136, 3979658311943880, 15908408006551904, 71162952082313488, 284082756324759560, 1019946695587234480
Offset: 1

Views

Author

Antti Karttunen, Sep 22 2024

Keywords

Comments

See comments in A376415.

Crossrefs

Programs

Formula

a(n) = A122242(4+n) XOR 16*A122242(n).

A057549 The local ranks of each term of A057547.

Original entry on oeis.org

0, 1, 3, 4, 8, 9, 11, 12, 13, 22, 23, 25, 26, 27, 31, 32, 34, 35, 36, 38, 39, 40, 41, 64, 65, 67, 68, 69, 73, 74, 76, 77, 78, 80, 81, 82, 83, 92, 93, 95, 96, 97, 101, 102, 104, 105, 106, 108, 109, 110, 111, 115, 116, 118, 119, 120, 122, 123, 124, 125, 127, 128, 129
Offset: 0

Views

Author

Antti Karttunen, Sep 07 2000

Keywords

Crossrefs

Formula

a(n) = CatalanRank(floor(binwidth(A057547[n])/2), A057547[n])

A376405 Bitwise XOR (centrally aligned) of two consecutive terms of A122245.

Original entry on oeis.org

176, 584, 2068, 9232, 38952, 135296, 567096, 2444568, 10136288, 34920688, 144732808, 625792608, 2598216176, 8989149792, 37119010736, 160422522664, 665656629200, 2297815400576, 9505629937992, 41066855413976, 169932530966160, 589165636912400, 2439104800321640, 10514745879265952, 43543845360254320, 149771860125187648
Offset: 1

Views

Author

Antti Karttunen, Sep 22 2024

Keywords

Crossrefs

Programs

Formula

a(n) = A122245(1+n) XOR 2*A122245(n).

A376415 a(n) = A122245(4+n) XOR 16*A122245(n).

Original entry on oeis.org

14488, 57880, 258096, 1033752, 3702824, 14821424, 66158736, 264831016, 948570032, 3798139024, 16949183552, 67829237680, 243080889928, 972279514176, 4341071097344, 17360471721544, 62225889019592, 248568875068928, 1111070190653712, 4438793067349704, 15908408008868528, 63634253845942544, 284082756299099488, 1136310075423425200
Offset: 1

Views

Author

Antti Karttunen, Sep 22 2024

Keywords

Comments

This seems to preserve more of the "wavy texture" present in A122245 than what A376412 does vis-a-vis A122242. Compare the corresponding illustrations.

Crossrefs

Programs

A083930 Map from binary trees of size n to the set of corresponding trivalent plane trees (tpt) represented as size 2n+1 general trees.

Original entry on oeis.org

0, 7, 49, 57, 439, 452, 515, 541, 585, 4612, 4631, 4757, 4795, 4865, 5455, 5468, 5744, 5795, 5865, 6268, 6294, 6433, 6688, 53200, 53226, 53448, 53500, 53604, 54935, 54954, 55430, 55501, 55605, 56356, 56394, 56601, 57003, 63294, 63313, 63439
Offset: 0

Views

Author

Antti Karttunen, May 13 2003

Keywords

Crossrefs

Inverse function: A083929. Positions of A083936 in A014486.

Formula

a(n) = A057548(A057123(n)).

A153242 Positions of general trees in A014486 whose degree is not one.

Original entry on oeis.org

0, 2, 4, 5, 6, 9, 10, 11, 12, 13, 14, 15, 16, 19, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40, 41, 42, 43, 44, 47, 51, 52, 53, 56, 60, 65, 66, 67, 68, 69, 70, 71, 72, 73, 74, 75, 76, 77, 78, 79, 80, 81, 82, 83, 84, 85, 86, 87, 88, 89, 90, 91, 92, 93
Offset: 0

Views

Author

Antti Karttunen, Dec 21 2008

Keywords

Crossrefs

I.e. such i that A057515(i) is not 1. Complement of A057548. For n>0, gives the indices of trees whose degree is greater than one. (At least two top-level branches).
Previous Showing 21-30 of 30 results.