A072645 -id:A072645 - cp's OEIS frontend

A072654 Maximum position in A072645 where the value n occurs.

0, 1, 4, 17, 161, 11107, 39099276, 308061560269405, 11825896447872143037989337832, 10770594215935749279482183269315609406974195761679603097, 5521577958796399352092495436683350598124375604156506049598913887505725118345928241211637687725414588844260433

Offset: 0

Antti Karttunen, Jun 02 2002

nonn

Binary width of each term: A072655. Cf. A072638, A072639, A072640.

a(10) from Sean A. Irvine, Oct 18 2024

A072643 Half of the binary width of the terms of A014486, the number of digits in A063171(n)/2.

Original entry on oeis.org

0, 1, 2, 2, 3, 3, 3, 3, 3, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6

Offset: 0

Antti Karttunen, Jun 02 2002

Paolo Xausa, Table of n, a(n) for n = 0..10000

Each value v occurs A000108(v) times. The maximum position for value v to occur is A014138(v). Permutations: A071673, A072644, A072645, A072660. Cf. also A002024, A072649.

a[n_] := Module[{i, c, a}, i = c = 0; a = 1; While[n>c, a *= (4*i+2)/(i+2); i++; c += a]; i];
Table[a[n], {n, 0, 104}] (* Jean-François Alcover, Dec 26 2017, from Sage code *)
Flatten[Array[Table[#, CatalanNumber[#]]&, 7, 0]] (* Paolo Xausa, Feb 13 2024 *)

def A072643(n) :
    i = c = 0; a = 1
    while n > c :
        a *= (4*i+2)/(2+i)
        i += 1; c += a
    return i
[A072643(n) for n in (0..100)] # Peter Luschny, Sep 07 2012

Sum_{n>=1} (-1)^(n+1)/a(n) = Sum_{n>=1} (-1)^(n+1)/(2^n-1) = 0.76449978034844420919... . - Amiram Eldar, Feb 18 2024

A071673 Sequence a(n) obtained by setting a(0) = 0; then reading the table T(x,y)=a(x)+a(y)+1 in antidiagonal fashion.

Original entry on oeis.org

0, 1, 2, 2, 3, 3, 3, 3, 4, 4, 3, 4, 4, 5, 4, 4, 4, 5, 5, 5, 5, 4, 4, 5, 6, 5, 6, 5, 4, 4, 5, 6, 6, 6, 6, 5, 4, 5, 5, 6, 6, 7, 6, 6, 5, 5, 5, 6, 6, 6, 7, 7, 6, 6, 6, 5, 4, 6, 7, 6, 7, 7, 7, 6, 7, 6, 4, 5, 5, 7, 7, 7, 7, 7, 7, 7, 7, 5, 5, 5, 6, 6, 7, 8, 7, 7, 7, 8, 7, 6, 6, 5, 6, 6, 7, 6, 8, 8, 7, 7, 8, 8, 6, 7, 6, 6

Offset: 0

Antti Karttunen, May 30 2002

The fixed point of RASTxx transformation. The repeated applications of RASTxx starting from A072643 seem to converge toward this sequence. Compare to A072768 from which this differs first time at the position n=37, where A072768(37) = 4, while A071673(37) = 5.
Each term k occurs A000108(k) times, and maximal position where k occurs is A072638(k).
The size of each Catalan structure encoded by the corresponding terms in triangles A071671 & A071672 (i.e., the number of digits / 2), as obtained with the global ranking/unranking scheme presented in A071651-A071654.

			The first 15 rows of this irregular triangular table:
               0,
               1,
              2, 2,
             3, 3, 3,
            3, 4, 4, 3,
           4, 4, 5, 4, 4,
          4, 5, 5, 5, 5, 4,
         4, 5, 6, 5, 6, 5, 4,
        4, 5, 6, 6, 6, 6, 5, 4,
       5, 5, 6, 6, 7, 6, 6, 5, 5,
      5, 6, 6, 6, 7, 7, 6, 6, 6, 5,
     4, 6, 7, 6, 7, 7, 7, 6, 7, 6, 4,
    5, 5, 7, 7, 7, 7, 7, 7, 7, 7, 5, 5,
   5, 6, 6, 7, 8, 7, 7, 7, 8, 7, 6, 6, 5,
  6, 6, 7, 6, 8, 8, 7, 7, 8, 8, 6, 7, 6, 6
etc.
E.g., we have
  a(1) = T(0,0) = a(0) + a(0) + 1 = 1,
  a(2) = T(1,0) = a(1) + a(0) + 1 = 2,
  a(3) = T(0,1) = a(0) + a(1) + 1 = 2,
  a(4) = T(2,0) = a(2) + a(0) + 1 = 3, etc.

Antti Karttunen, Table of n, a(n) for n = 0..10440 (rows 0..144 of the triangle, flattened)
N. J. A. Sloane, Transforms (Maple code for RASTxx transform)

Same triangle computed modulo 2: A071674.
Permutations of this sequence include: A072643, A072644, A072645, A072660, A072768, A072789, A075167.
Cf. also A000108, A002260, A004736, A002262, A025581, A072638.

up_to = 105;
A002260(n) = (n-binomial((sqrtint(8*n)+1)\2, 2)); \\ From A002260
A004736(n) = (1-n+(n=sqrtint(8*n)\/2)*(n+1)\2); \\ From A004736
A071673list(up_to) = { my(v=vector(1+up_to)); v[1] = 0; for(n=1,up_to,v[1+n] = 1 + v[A004736(n)] + v[A002260(n)]); (v); };
v071673 = A071673list(up_to);
A071673(n) = v071673[1+n]; \\ Antti Karttunen, Aug 17 2021

(define (A071673 n) (cond ((zero? n) n) (else (+ 1 (A071673 (A025581 (-1+ n))) (A071673 (A002262 (-1+ n)))))))

a(0) = 0, a(n) = 1 + a(A025581(n-1)) + a(A002262(n-1)) = 1 + a(A004736(n)) + a(A002260(n)).

Self-referential definition added Jun 03 2002

Term a(0) = 0 prepended and the Example-section amended by Antti Karttunen, Aug 17 2021

A072644 Size of the parenthesizations obtained with the global ranking/unranking scheme A072634-A072637.

Original entry on oeis.org

0, 1, 2, 2, 3, 3, 3, 4, 4, 3, 4, 3, 4, 5, 5, 5, 5, 4, 4, 5, 5, 4, 5, 5, 6, 6, 6, 6, 6, 6, 7, 6, 7, 4, 5, 4, 5, 6, 6, 6, 6, 4, 5, 5, 6, 6, 6, 7, 7, 7, 7, 7, 7, 7, 8, 7, 8, 7, 7, 8, 8, 7, 8, 8, 9, 5, 4, 6, 5, 5, 4, 6, 5, 7, 6, 7, 6, 7, 6, 7, 6, 5, 6, 6, 7, 6, 6, 7, 7, 7, 8, 7, 8, 8, 8, 8, 8, 8, 7, 8, 7, 8, 7, 8, 7

Offset: 0

Antti Karttunen, Jun 02 2002

nonn

Sohrab Towfighi, Symbolic regression by random search, arXiv:1906.07848 [cs.NE], 2019.

Cf. A072635 & A072637. A072644(n) = A029837(A014486(A072635(n))+1)/2 or = A029837(A014486(A072637(n))+1)/2 [A029837(n+1) gives the binary width of n].

Each value v occurs A000108(v) times. The maximum position for value v to occur is A072639(v). Permutations: A071673, A072643, A072645, A072660.

A072660 Size of the parenthesizations obtained with the global ranking/unranking scheme A072656-A072659.

Original entry on oeis.org

0, 1, 2, 2, 3, 3, 3, 3, 4, 4, 4, 3, 5, 4, 4, 4, 5, 4, 4, 6, 5, 5, 5, 5, 4, 6, 5, 4, 4, 5, 7, 6, 6, 6, 5, 5, 5, 6, 5, 5, 7, 6, 6, 6, 5, 4, 6, 5, 8, 7, 7, 7, 6, 7, 6, 6, 6, 6, 5, 7, 6, 5, 4, 6, 8, 7, 7, 7, 6, 6, 5, 7, 5, 5, 8, 6, 6, 9, 8, 8, 8, 7, 8, 7, 7, 9, 7, 7, 7, 6, 6, 5, 7, 5, 6, 8, 7, 7, 6, 6, 4, 7, 5, 9, 8

Offset: 0

Antti Karttunen, Jun 02 2002

nonn

Cf. A072657-A072659. Permutations: A071673, A072643, A072644, A072645.

A072768 The RASTxx transformation of the sequence A072643.

Original entry on oeis.org

1, 2, 2, 3, 3, 3, 3, 4, 4, 3, 4, 4, 5, 4, 4, 4, 5, 5, 5, 5, 4, 4, 5, 6, 5, 6, 5, 4, 4, 5, 6, 6, 6, 6, 5, 4, 4, 5, 6, 6, 7, 6, 6, 5, 4, 5, 5, 6, 6, 7, 7, 6, 6, 5, 5, 5, 6, 6, 6, 7, 7, 7, 6, 6, 6, 5, 5, 6, 7, 6, 7, 7, 7, 7, 6, 7, 6, 5, 5, 6, 7, 7, 7, 7, 7, 7, 7, 7, 7, 6, 5, 5, 6, 7, 7, 8, 7, 7, 7, 7, 8, 7, 7, 6, 5

Offset: 1

Antti Karttunen, Jun 12 2002

Also, the sizes of the parenthesizations produced by 'cons' combination A072764 and its transpose A072766.
Differs from A071673 first time at the position n=37, where A072768(37) = 4, while A071673(37) = 5. RASTxx(A072768) differs from A071673 first time at the position n=704, which leads to conjecture that the repeated applications of RASTxx starting from A072643 converge towards A071673, the fixed point of RASTxx transformation.
Each value v occurs A000108(v) times. (The term a(0)=0 is not explicitly listed here as to get a better looking triangle).

A. Karttunen, Gatomorphisms (Includes the complete Scheme source for computing this sequence)
N. J. A. Sloane, Transforms (Maple code for RASTxx transform)

Same triangle computed modulo 2: A072770. Permutations: A072643, A071673, A072644, A072645, A072660, A072789. Cf. also A072769, A025581, A002262.

(define (A072768 n) (cond ((zero? n) n) (else (+ 1 (A072643 (A025581 (-1+ n))) (A072643 (A002262 (-1+ n)))))))

A072647 a(n) = A072637(A048679(n)).

Original entry on oeis.org

0, 1, 2, 6, 3, 15, 4, 5, 52, 7, 16, 19, 14, 466, 11, 9, 37, 8, 112, 42, 43, 5095, 20, 53, 44, 39, 127, 10, 28, 481, 123, 121, 149, 51, 17231, 29, 12, 40, 17, 41, 154, 155, 153, 18, 47, 156, 38, 1512, 477, 475, 385, 151, 1234, 122, 376, 69829, 55, 159, 56, 113, 164

Offset: 0

Antti Karttunen, Jun 02 2002

nonn

Composition of the permutations A072637 & A048679.

A. Karttunen, Gatomorphisms
Index entries for sequences that are permutations of the natural numbers

A072645 gives the size of the corresponding parenthesizations, i.e., A072645(n) = A029837(A014486(A072647(n)) + 1)/2. (A029837(n+1) gives the binary width of n.)

cp's OEIS Frontend

A072654 Maximum position in A072645 where the value n occurs.

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A072643 Half of the binary width of the terms of A014486, the number of digits in A063171(n)/2.

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A071673 Sequence a(n) obtained by setting a(0) = 0; then reading the table T(x,y)=a(x)+a(y)+1 in antidiagonal fashion.

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A072644 Size of the parenthesizations obtained with the global ranking/unranking scheme A072634-A072637.

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A072660 Size of the parenthesizations obtained with the global ranking/unranking scheme A072656-A072659.

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A072768 The RASTxx transformation of the sequence A072643.

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A072647 a(n) = A072637(A048679(n)).

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