A137560 -id:A137560 - cp's OEIS frontend

A137867 Triangular sequence of coefficients of the Misiurewicz polynomial which are made from the Pc Mandelbrot -Julia polynomials A137560 as: Pc(x,n)-Pc(x,m); n<>m.

-1, 1, 0, 0, 1, -1, 1, 1, 0, 0, 0, 2, 1, 0, 0, 1, 2, 1, -1, 1, 1, 2, 1, 0, 0, 0, 0, 4, 6, 6, 4, 1, 0, 0, 0, 2, 5, 6, 6, 4, 1, 0, 0, 1, 2, 5, 6, 6, 4, 1, -1, 1, 1, 2, 5, 6, 6, 4, 1, 0, 0, 0, 0, 0, 8, 20, 40, 68, 94, 114, 116, 94, 60, 28, 8, 1, 0, 0, 0, 0, 4, 14, 26, 44, 69, 94, 114, 116, 94, 60, 28, 8, 1, 0, 0, 0, 2, 5, 14, 26, 44, 69, 94, 114, 116, 94, 60, 28, 8

Offset: 1

Roger L. Bagula, Apr 29 2008

Row sums are: {0, 1, 1, 3, 4, 4, 21, 24, 25, 25, 651, 672, 675, 676, 676, 457653, 458304, 458325, 458328, 458329, 458329};

The roots of these polynomials are called Misiurewicz points and they are found in the antenna areas of the Mandelbrot set M.

			{-1, 1},
{0, 0, 1},
{-1, 1, 1},
{0, 0, 0, 2, 1},
{0, 0, 1, 2, 1},
{-1, 1, 1, 2, 1},
{0, 0, 0, 0, 4, 6, 6, 4, 1},
{0, 0, 0, 2, 5, 6, 6, 4, 1},
{0, 0, 1, 2, 5, 6, 6, 4, 1},
{-1, 1, 1, 2, 5, 6, 6, 4, 1},
{0, 0, 0, 0, 0, 8, 20, 40, 68, 94, 114, 116, 94, 60, 28, 8, 1},
{0, 0, 0, 0, 4, 14, 26, 44, 69, 94, 114, 116, 94, 60, 28, 8, 1},
{0, 0, 0, 2,5, 14, 26, 44, 69, 94, 114, 116, 94, 60, 28, 8, 1},
{0, 0, 1, 2, 5, 14, 26, 44, 69, 94, 114, 116, 94, 60, 28, 8, 1},
{-1, 1, 1, 2, 5, 14, 26, 44, 69, 94, 114, 116, 94, 60, 28, 8, 1},
{0, 0, 0, 0, 0, 0, 16, 56, 152, 376, 844, 1744, 3340, 5976, 10040, 15856, 23460, 32398, 41658, 49700, 54746, 55308, 50788, 41944, 30782, 19788, 10948, 5096, 1932, 568, 120, 16, 1},
{0, 0, 0, 0, 0, 8, 36, 96, 220, 470, 958, 1860, 3434, 6036, 10068, 15864, 23461, 32398, 41658, 49700, 54746, 55308, 50788, 41944, 30782, 19788, 10948, 5096, 1932, 568, 120, 16, 1},
{0, 0, 0, 0, 4, 14, 42, 100, 221, 470, 958, 1860, 3434, 6036, 10068, 15864, 23461, 32398, 41658, 49700, 54746, 55308, 50788, 41944, 30782, 19788, 10948, 5096, 1932, 568, 120, 16, 1},
{0, 0, 0, 2, 5, 14, 42, 100, 221, 470, 958, 1860, 3434, 6036, 10068, 15864, 23461, 32398, 41658, 49700, 54746, 55308, 50788, 41944, 30782, 19788, 10948, 5096, 1932, 568, 120, 16, 1},
{0, 0, 1, 2, 5, 14, 42, 100, 221, 470, 958, 1860, 3434, 6036, 10068, 15864, 23461, 32398, 41658, 49700, 54746, 55308, 50788, 41944, 30782, 19788, 10948, 5096, 1932, 568, 120, 16, 1},
{-1, 1, 1, 2, 5, 14, 42, 100, 221, 470, 958, 1860, 3434, 6036, 10068, 15864, 23461, 32398, 41658, 49700, 54746, 55308, 50788, 41944, 30782, 19788, 10948, 5096, 1932, 568, 120, 16, 1}

Lennart Carleson and Theodore W. Gamelin, Complex Dynamics, Springer, New York, 1993, p. 133ff.

Clear[f, g, h, x]; f[z_] = z^2 + x; g = Join[{1}, ExpandAll[NestList[f, x, 5]]]; h = Union[Flatten[Table[Flatten[Table[If[n == m, {}, ExpandAll[g[[ n]] - g[[m]]]], {m, 1, n}]], {n, 1, Length[g]}]]]; a = Table[CoefficientList[h[[n]], x], {n, 1, Length[h]}]; Flatten[a] Table[Apply[Plus, CoefficientList[h[[n]], x]], {n, 1, Length[h]}];

Pc(x,n)-> Nested ( z^2+x: when z->x): A137560; Pc(x,n)-Pc(x,m); n<>m;

A003095 a(n) = a(n-1)^2 + 1 for n >= 1, with a(0) = 0.

Original entry on oeis.org

0, 1, 2, 5, 26, 677, 458330, 210066388901, 44127887745906175987802, 1947270476915296449559703445493848930452791205, 3791862310265926082868235028027893277370233152247388584761734150717768254410341175325352026

Offset: 0

N. J. A. Sloane and Richard Stanley

Number of binary trees of height less than or equal to n. [Corrected by Orson R. L. Peters, Jan 03 2020]
The rightmost digits cycle (0,1,2,5,6,7,0,1,2,5,6,7,...). - Jonathan Vos Post, Jul 21 2005
Apart from the initial term, a subsequence of A008318. - Reinhard Zumkeller, Jan 17 2008
Partial sums of A001699. - Jonathan Vos Post, Feb 17 2010
Corresponds to the second and second last diagonals of A119687. - John M. Campbell, Jul 25 2011
This is a divisibility sequence. - Michael Somos, Jan 01 2013
Sum_{n>=1} 1/a(n) = 1.739940825174794649210636285335916041018367182486941... . - Vaclav Kotesovec, Jan 30 2015
From Vladimir Vesic, Oct 03 2015: (Start)
Forming Herbrand's domains of formula: (∃x)(∀y)(∀z)(∃k)(P(x)∨Q(y)∧R(k))
where: x->a
       k->f(y,z)
we get:
  H0 = {a}
  H1 = {a, f(a,a)}
  H2 = {a, f(a,a), f(a,f(a,a)), f(f(a,a),a), f(f(a,a),f(a,a))}
  ...
The number of elements in each domain follows this sequence.
(End)
It is an open question whether or not this sequence satisfies Benford's law [Berger-Hill, 2017] - N. J. A. Sloane, Feb 07 2017
This is a strong divisibility sequence; see A329429. - Clark Kimberling, Nov 13 2019
From Peter Bala, Oct 31 2022: (Start)
Let k be a positive integer. Clearly, the sequence obtained by reducing a(n) modulo k is eventually periodic. Conjectures:
1) The sequence obtained by reducing a(n) modulo 2^k is eventually periodic with period 2.
2) The sequence obtained by reducing a(n) modulo 10^k is eventually periodic with period 6 (the case k = 1 is noted above).
3) The sequence obtained by reducing a(n) modulo 20^k is eventually periodic with period 6.
4) For n >= floor(k/2) and for 1 <= i <= 6, the value of a(6*n+i) mod 10^k is a constant independent of n. The digits of these 6 constant integers, when read from right to left, are the first k digits of the 10-adic numbers A318135 (i = 1), A318136 (i = 2), A318137 (i = 3), A318138 (i = 4), A318139 (i = 5) and A318140 (i = 6), respectively. An example is given below.
  n      a(6*n+1) mod 10^11
1           10066388901
2           72084948901
3           67988948901
4           61588948901
5           01588948901
6           01588948901
7           01588948901
...             ...
A318135 begins 1, 0, 9, 8, 4, 9, 8, 8, 5, 1, 0, 2, .... (End)

Mordechai Ben-Ari, Mathematical Logic for Computer Science, Third edition, 173-203.
S. R. Finch, Mathematical Constants, Cambridge, 2003, pp. 443-448.
R. K. Guy, How to factor a number, Proc. 5th Manitoba Conf. Numerical Math., Congress. Num. 16 (1975), 49-89.
R. Penrose, The Emperor's New Mind, Oxford, 1989, p. 122.
N. J. A. Sloane and Simon Plouffe, The Encyclopedia of Integer Sequences, Academic Press, 1995 (includes this sequence).

Alois P. Heinz, Table of n, a(n) for n = 0..13
A. V. Aho and N. J. A. Sloane, Some doubly exponential sequences, Fibonacci Quarterly, Vol. 11, No. 4 (1973), pp. 429-437.
A. V. Aho and N. J. A. Sloane, Some doubly exponential sequences, Fibonacci Quarterly, Vol. 11, No. 4 (1973), pp. 429-437 (original plus references that F.Q. forgot to include - see last page!)
A. Berger and T. P. Hill, What is Benford's Law?, Notices, Amer. Math. Soc., 64:2 (2017), 132-134.
Neil J. Calkin, Eunice Y. S. Chan, and Robert M. Corless, Some Facts and Conjectures about Mandelbrot Polynomials, Maple Transactions (2021) Vol. 1, No. 1, Article 1.
P. Flajolet and A. M. Odlyzko, Limit distributions of coefficients of iterates of polynomials with applications to combinatorial enumerations, Math. Proc. Camb. Phil. Soc., 96 (1984), 237-253.
Claudio Gentile, Fabio Vitale, and Anand Rajagopalan, Flattening a Hierarchical Clustering through Active Learning, arXiv:1906.09458 [cs.LG], 2019.
Spencer Hamblen, Rafe Jones, and Kalyani Madhu, The density of primes in orbits of z^d + c, arXiv:1303.6513 [math.NT], 2013; to appear, Int. Math. Res. Not., c. 2015.
Dimitur Krustev, Simple Programs on Binary Trees Testing and Decidable Equivalence, 2016.
Robin Lamarche-Perrin, An Information-theoretic Framework for the Lossy Compression of Link Streams, arXiv:1807.06874 [cs.DS], 2018.
R. Lamarche-Perrin, Y. Demazeau, and J.-M. Vincent, A Generic Algorithmic Framework to Solve Special Versions of the Set Partitioning Problem, Preprint 105, Max-Planck-Institut fur Mathematik in den Naturwissenschaften, Leipzig, 2014.
C. Lenormand, Arbres et permutations II, see p. 6.
Saad Mneimneh, Simple Variations on the Tower of Hanoi to Guide the Study of Recurrences and Proofs by Induction, Department of Computer Science, Hunter College, CUNY, 2019.
Michael Penn, a stylish proof that..., YouTube video, 2021.
R. P. Stanley, Letter to N. J. A. Sloane, c. 1991
M. Tainiter, Algebraic approach to stopping variable problems: Representation theory and applications, J. Combinatorial Theory 9 1970 148-161.
P. Tarau, A Logic Programming Playground for Lambda Terms, Combinators, Types and Tree-based Arithmetic Computations, arXiv preprint arXiv:1507.06944 [cs.LO], 2015.
Stephan Wagner and Volker Ziegler, Irrationality of growth constants associated with polynomial recursions, arXiv:2004.09353 [math.NT], 2020.
Wikipedia, Herbrand Structure
Damiano Zanardini, Computational Logic, UPM European Master in Computational Logic (EMCL) School of Computer Science Technical University of Madrid.
Index entries for sequences of form a(n+1)=a(n)^2 + ...
Index to divisibility sequences
Index entries for sequences related to Benford's law

Cf. A001699, A004019, A038044, A056207, A076949, A077496, A091980, A143848.
Cf. A143849, A213437, A247981, A248218, A248219, A318135, A318136, A318137.
Cf. A318138, A318139, A318140, A355108.
Cf. A137560, which enumerates binary trees of height less than n and exactly j leaf nodes. - Robert Munafo, Nov 03 2009

function A003095(n)
  if n eq 0 then return 0;
  else return 1 + A003095(n-1)^2;
  end if; return A003095;
end function;
[A003095(n): n in [0..12]]; // G. C. Greubel, Nov 29 2022

a:= proc(n) option remember; `if`(n=0, 0, a(n-1)^2+1) end:
seq(a(n), n=0..10);  # Alois P. Heinz, Jul 11 2019

NestList[#^2+1&,0,10] (* Harvey P. Dale, Dec 17 2010 *)

{a(n) = if( n<1, 0, 1 + a(n-1)^2)}; /* Michael Somos, Jan 01 2013 */

def A003095(n): return 0 if (n==0) else 1 + A003095(n-1)^2
[A003095(n) for n in range(13)] # G. C. Greubel, Nov 29 2022

a(n) = B_{n-1}(1) where B_n(x) = 1 + x*B_{n-1}(x)^2 is the generating function of trees of height <= n.
a(n) is asymptotic to c^(2^n) where c=1.2259024435287485386279474959130085213... (see A076949). - Benoit Cloitre, Nov 27 2002
c = b^(1/4) where b is the constant in Bottomley's formula in A004019. a(n) appears very asymptotic to c^(2^n) - Sum_{k>=1} A088674(k)/(2*c^(2^n))^(2*k-1). - Gerald McGarvey, Nov 17 2007
a(n) = Sum_{i=1..n} A001699(i). - Jonathan Vos Post, Feb 17 2010
G.f. = x + 2*x^2 + 5*x^3 + 26*x^4 + 677*x^5 + 458330*x^6 + 210066388901*x^7 + ... . - Michael Somos, Jan 01 2013
a(2n) mod 2 = 0 ; a(2n+1) mod 2 = 1. - Altug Alkan, Oct 04 2015
a(n) + a(n-1) = A213437(n). - Peter Bala, Feb 03 2017
0 = a(n)^2*(+a(n+1) + a(n+2)) + a(n+1)^2*(-a(n+1) - a(n+2) - a(n+3)) + a(n+2)^3 for all n>=0. - Michael Somos, Feb 10 2017
a(n) = A091980(2^(n-1)) for n > 0. - Alois P. Heinz, Jul 11 2019

Additional comments from Cyril Banderier, Jun 05 2000
Minor edits by Vaclav Kotesovec, Oct 04 2014
Initial term clarified by Clark Kimberling, Nov 13 2019

A309049 Number T(n,k) of (binary) max-heaps on n elements from the set {0,1} containing exactly k 0's; triangle T(n,k), n>=0, 0<=k<=n, read by rows.

Original entry on oeis.org

1, 1, 1, 1, 1, 1, 1, 2, 1, 1, 1, 2, 2, 1, 1, 1, 3, 3, 2, 1, 1, 1, 3, 4, 4, 2, 1, 1, 1, 4, 6, 6, 5, 2, 1, 1, 1, 4, 7, 8, 7, 5, 2, 1, 1, 1, 5, 10, 12, 11, 8, 5, 2, 1, 1, 1, 5, 11, 16, 17, 13, 9, 5, 2, 1, 1, 1, 6, 15, 23, 27, 24, 16, 10, 5, 2, 1, 1, 1, 6, 16, 27, 34, 34, 27, 18, 11, 5, 2, 1, 1

Offset: 0

Alois P. Heinz, Jul 09 2019

Also the number T(n,k) of (binary) min-heaps on n elements from the set {0,1} containing exactly k 1's.

The sequence of column k satisfies a linear recurrence with constant coefficients of order A063915(k).

			T(6,0) = 1: 111111.
T(6,1) = 3: 111011, 111101, 111110.
T(6,2) = 4: 110110, 111001, 111010, 111100.
T(6,3) = 4: 101001, 110010, 110100, 111000.
T(6,4) = 2: 101000, 110000.
T(6,5) = 1: 100000.
T(6,6) = 1: 000000.
T(7,4) = T(7,7-3) = A000108(3) = 5: 1010001, 1010010, 1100100, 1101000, 1110000.
Triangle T(n,k) begins:
  1;
  1, 1;
  1, 1,  1;
  1, 2,  1,  1;
  1, 2,  2,  1,  1;
  1, 3,  3,  2,  1,  1;
  1, 3,  4,  4,  2,  1,  1;
  1, 4,  6,  6,  5,  2,  1,  1;
  1, 4,  7,  8,  7,  5,  2,  1,  1;
  1, 5, 10, 12, 11,  8,  5,  2,  1, 1;
  1, 5, 11, 16, 17, 13,  9,  5,  2, 1, 1;
  1, 6, 15, 23, 27, 24, 16, 10,  5, 2, 1, 1;
  1, 6, 16, 27, 34, 34, 27, 18, 11, 5, 2, 1, 1;
  ...

Alois P. Heinz, Rows n = 0..200, flattened
Eric Weisstein's World of Mathematics, Heap
Wikipedia, Binary heap

Columns k=0-10 give: A000012, A110654, A114220 (for n>0), A326504, A326505, A326506, A326507, A326508, A326509, A326510, A326511.
Row sums give A091980(n+1).
T(2n,n) gives A309050.
Rows reversed converge to A000108.
Cf. A000225, A000295, A003095, A024358, A056971, A063915, A137560, A168542, A202019, A309051, A309052.

b:= proc(n) option remember; `if`(n=0, 1, (g-> (f-> expand(
      x^n+b(f)*b(n-1-f)))(min(g-1, n-g/2)))(2^ilog2(n)))
    end:
T:= n-> (p-> seq(coeff(p, x, i), i=0..n))(b(n)):
seq(T(n), n=0..14);

b[n_] := b[n] = If[n == 0, 1, Function[g, Function[f, Expand[x^n + b[f]*b[n - 1 - f]]][Min[g - 1, n - g/2]]][2^Floor[Log[2, n]]]];
T[n_] := Function[p, Table[Coefficient[p, x, i], {i, 0, n}]][b[n]];
T /@ Range[0, 14] // Flatten (* Jean-François Alcover, Oct 04 2019, after Alois P. Heinz *)

Sum_{k=0..n}    k  * T(n,k) = A309051(n).
Sum_{k=0..n} (n-k) * T(n,k) = A309052(n).
Sum_{k=0..2^n-1} T(2^n-1,k) = A003095(n+1).
Sum_{k=0..2^n-1} (2^n-1-k) * T(2^n-1,k) = A024358(n).
Sum_{k=0..n} (T(n,k) - T(n-1,k)) = A168542(n).
T(m,m-n) = A000108(n) for m >= 2^n-1 = A000225(n).
T(2^n-1,k) = A202019(n+1,k+1).

A202019 Triangle by rows, related to the numbers of binary trees of height less than n, derived from the Mandelbrot set.

Original entry on oeis.org

1, 1, 1, 1, 2, 1, 1, 1, 4, 6, 6, 5, 2, 1, 1, 1, 8, 28, 60, 94, 116, 114, 94, 69, 44, 26, 14, 5, 2, 1, 1, 1, 16, 120, 568, 1932, 5096, 10948, 19788, 30782, 41944, 50788, 55308, 54746, 49700, 41658, 32398, 23461, 15864, 10068, 6036, 3434, 1860, 958, 470, 221, 100, 42, 14, 5, 2, 1, 1

Offset: 1

Gary W. Adamson, Dec 08 2011

As shown on p. 74 [Diaconis & Graham], n-th row polynomials are cyclic with period n, given real roots, if the polynomials are divided through by n. For example, taking x^3 + 2x^2 + x + 1 = 0, the real root = -1.75487766... = c. Then using x^2 + c, we obtain the period three trajectory: -1.75487... -> 1.32471...-> 0.
The shuffling connection [p.75], resulting in a permutation that is the Gilbreath shuffle: "To make the connection with shuffling cards, write down a periodic sequence starting at zero. Write a one above the smallest point, a two above the next smallest point and so on. For example, if c = -1.75486...(a period three point), we have:
2.............1.............3......
0........-1.75487........1.32471... For a fixed value of c, the numbers written on top code up a permutation that is a Gilbreath shuffle".
Row sums = A003095: (1, 2, 5, 26, 677,...) relating to the number of binary trees of height less than n.
Let f(z) = z^2 + c, then row k lists the expansion of the n-fold composition f(f(...f(0)...)) in falling powers of c (with the coefficients for c^0 omitted). The n initial terms of the reversed n-th row are the Catalan numbers (cf. A137560). - Joerg Arndt, Jun 04 2016

			Row 4 = (1, 4, 6, 6, 5, 2, 1, 1) since (x^4 + 2x^3 + x^2 + x)^2 + x = x^8 + 4x^7 + 6x^6 + 6x^5 + 5x^4 + 2x^3 + x^2 + x.
Triangle begins:
  1;
  1, 1;
  1, 2,  1,  1;
  1, 4,  6,  6,  5,   2,   1,  1;
  1, 8, 28, 60, 94, 116, 114, 94, 69, 44, 26, 14, 5, 2, 1, 1;
  ...

Persi Diaconis & R. L. Graham, "Magical Mathematics: The Mathematical Ideas That Animate Great Magic Tricks", Princeton University Press, 2012; pp. 73-83.

Alois P. Heinz, Rows n = 1..13, flattened
Juan Carlos Nuño and Francisco J. Muñoz, Entropy-Variance curves of binary sequences generated by random substitutions of constant length, arXiv:2112.15563 [math.PR], 2021.

Row sums are A003095.
Cf. A137560 (reversed rows).
Cf. A309049.

b:= proc(n) option remember; `if`(n=0, 1, (g-> (f-> expand(
      x^n+b(f)*b(n-1-f)))(min(g-1, n-g/2)))(2^ilog2(n)))
    end:
T:= n-> (p-> seq(coeff(p, x, i), i=0..degree(p)))(b(2^(n-1)-1)):
seq(T(n), n=1..7);  # Alois P. Heinz, Jul 11 2019

b[n_] := b[n] = If[n == 0, 1, Function[g, Function[f, Expand[x^n + b[f]*
     b[n-1-f]]][Min[g-1, n-g/2]]][2^(Length[IntegerDigits[n, 2]]-1)]];
T[n_] := CoefficientList[b[2^(n-1)-1], x];
Array[T, 7] // Flatten (* Jean-François Alcover, Feb 19 2021, after Alois P. Heinz *)

Coefficients of x by rows such that given n-th row p(x), the next row is (p(x))^2 + x; starting x -> (x^2 + x) -> (x^4 + 2*x^3 + x^2 + x)...

T(n,k) = A309049(2^(n-1)-1,k-1). - Alois P. Heinz, Jul 11 2019

A347928 Triangle read by rows, T(n, k) are the coefficients of the scaled Mandelbrot-Larsen polynomials P(n, x) = 2^(2n-1)M(n, x), where M(n, x) are the Mandelbrot-Larsen polynomials; for 0 <= k <= n.

Original entry on oeis.org

0, 0, 1, 0, 2, 1, 0, 0, 4, 2, 0, 16, 12, 12, 5, 0, 0, 32, 40, 40, 14, 0, 0, 192, 208, 168, 140, 42, 0, 0, 0, 640, 800, 720, 504, 132, 0, 2048, 1792, 2688, 3920, 3584, 3080, 1848, 429, 0, 0, 4096, 4608, 11520, 17760, 16512, 13104, 6864, 1430

Offset: 0

Peter Luschny, Oct 27 2021

To avoid confusion: the polynomials which are called 'Mandelbrot polynomials' by some authors are listed in A137560. The name 'Mandelbrot-Larsen' polynomials was introduced in Calkin, Chan, & Corless to distinguish them from the Mandelbrot polynomials.

			Triangle starts:
[0]  0;
[1]  0,    1;
[2]  0,    2,    1;
[3]  0,    0,    4,    2;
[4]  0,   16,   12,   12,     5;
[5]  0,    0,   32,   40,    40,    14;
[6]  0,    0,  192,  208,   168,   140,    42;
[7]  0,    0,    0,  640,   800,   720,   504,   132;
[8]  0, 2048, 1792, 2688,  3920,  3584,  3080,  1848,  429;
[9]  0,    0, 4096, 4608, 11520, 17760, 16512, 13104, 6864, 1430.

Neil J. Calkin, Eunice Y. S. Chan, and Robert M. Corless, Some Facts and Conjectures about Mandelbrot Polynomials, Maple Trans., Vol. 1, No. 1, Article 14037 (July 2021).
V. P. Johnson, Enumeration Results on Leaf Labeled Trees, Ph. D. Dissertation, Univ. Southern Calif., 2012.
Michael Larsen, Multiplicative series, modular forms, and Mandelbrot polynomials, in: Mathematics of Computation 90.327 (Sept. 2020), pp. 345-377. Preprint: arXiv:1908.09974 [math.NT], 2019.

Cf. A137560, A000108, A000984, A001190, A083563, A088674, A048896, A107087, A220816, A220817.

Cf. A319539, A348678, A348679, A348686.

M := proc(n, x) local k; option remember;
if n = 0 then 0 elif n = 1 then x else add(M(k, x)*M(n-k, x), k = 1..n-1) +
ifelse(n::even, M(n/2, x), 0) fi; expand(%/2) end:
P := n -> 2^(2*n - 1)*M(n, x):
row := n -> seq(coeff(P(n), x, k), k = 0..n): seq(row(n), n = 0..9);

M[n_, x_] := M[n, x] = Module[{k, w}, w = Which[n == 0, 0, n == 1, x, True, Sum[M[k, x]*M[n-k, x], {k, 1, n-1}] + If[EvenQ[n], M[n/2, x], 0]]; Expand[w/2]];
P[n_] := 2^(2*n - 1)*M[n, x];
row [n_] := If[n == 0, {0}, CoefficientList[P[n], x]];
Table[row[n], {n, 0, 9}] // Flatten (* Jean-François Alcover, Jul 07 2022, after Maple code *)

The Mandelbrot-Larsen polynomials are defined: M(0, x) = 0; M(1, x) = x/2;
M(n, x) = (1/2)*(even(n)*M(n/2, x) + Sum_{k=1..n-1} M(k, x)*M(n-k, x)) for n > 1. Here even(n) = 1 if n is even, otherwise 0.
P(n, x) = 2^(2*n-1)*M(n, x) (scaled Mandelbrot-Larsen polynomials).
T(n, k) = [x^k] P(n, x).
[x^k] M(n,k) = A348679(n, k) / A348678(n, k).
M(n, 2*k) = P(n, 2*k) / 2^(2*n-1) = A319539(n, k).
P(n, k) = A348686(n, k).
T(n, n) = A000108(n-1) for n >= 1, Catalan numbers.
T(n+2, n+1) / 2 = A000984(n) for n >= 0, central binomials.
P(n, 1) = A088674(n-1) for n >= 1, also row sums.
M(n, 2) = A001190(n) for n >= 0.
M(n, 4) = A083563(n) for n >= 0.
M(n,-4) = -A107087(n) for n >= 1.
M(n, 6) = A220816(n) for n >= 1.
M(n, 8) = A220817(n) for n >= 1.
Conjecture (Calkin, Chan, & Corless): content(P(n)) = gcd(row(n)) = A048896(n-1) for n >= 1.

A052154 Array read by antidiagonals: a(n,k)= coefficient of z^n of p_k(z), where p_k+1(z)=(p_k(z))^2+z, p_1(z)=z.

Original entry on oeis.org

1, 1, 0, 1, 1, 0, 1, 1, 0, 0, 1, 1, 2, 0, 0, 1, 1, 2, 1, 0, 0, 1, 1, 2, 5, 0, 0, 0, 1, 1, 2, 5, 6, 0, 0, 0, 1, 1, 2, 5, 14, 6, 0, 0, 0, 1, 1, 2, 5, 14, 26, 4, 0, 0, 0, 1, 1, 2, 5, 14, 42, 44, 1, 0, 0, 0, 1, 1, 2, 5, 14, 42, 100, 69, 0, 0, 0, 0

Offset: 1

Klaus Strassburger (strass(AT)ddfi.uni-duesseldorf.de), Jan 24 2000

a(n,k+1)=a(n,k), n<=k; a(n,n)=A000108. Note that the set {z: limit(p_k(z),k->infinity) not=infinity} of complex numbers defines the Mandelbrot set.

			p_1(z)=z: coefficient = 1 = a(1,1); p_2(z)=z^2+z: coefficients = 1, 1 = a(1,2), a(2,2); p_3(z)=(z^2+z)^2+z=z+z^2+2z^3+z^4: coefficients = 1,1,2,1 = (1,3), a(2,3), a(3,3), a(4,3); ...
Triangle starts:
1,
1, 0,
1, 1, 0,
1, 1, 0, 0,
1, 1, 2, 0, 0,
1, 1, 2, 1, 0, 0,
1, 1, 2, 5, 0, 0, 0,
1, 1, 2, 5, 6, 0, 0, 0,
1, 1, 2, 5, 14, 6, 0, 0, 0,
1, 1, 2, 5, 14, 26, 4, 0, 0, 0,
1, 1, 2, 5, 14, 42, 44, 1, 0, 0, 0,
1, 1, 2, 5, 14, 42, 100, 69, 0, 0, 0, 0,
...

R. P. Munafo, Mu-Ency - The Encyclopedia of the Mandelbrot Set
Eric Weisstein's World of Mathematics, Mandelbrot Set
R. Munafo, Coefficients of Lemniscates for Mandelbrot Set

Cf. A000108.

Cf. A137560, which gives the same array read by rows. [From Robert Munafo, Dec 12 2009]

p[1, z_] := z; p[k_, z_] := p[k, z] = p[k-1, z]^2 + z; a[n_, k_] := Coefficient[p[k, z], z, n]; Flatten[ Table[a[n-k, k], {n, 1, 13}, {k, n-1, 1, -1}]] (* Jean-François Alcover, Jun 13 2012 *)

a(n, k+1)=sum(a(i, k)*a(n-i, k), i=1..n-1) for n=2..2^k, a(1, k)=1, a(n, k+1)=0 for n>2^k.

cp's OEIS Frontend

A137867 Triangular sequence of coefficients of the Misiurewicz polynomial which are made from the Pc Mandelbrot -Julia polynomials A137560 as: Pc(x,n)-Pc(x,m); n<>m.

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A003095 a(n) = a(n-1)^2 + 1 for n >= 1, with a(0) = 0.

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A309049 Number T(n,k) of (binary) max-heaps on n elements from the set {0,1} containing exactly k 0's; triangle T(n,k), n>=0, 0<=k<=n, read by rows.

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A202019 Triangle by rows, related to the numbers of binary trees of height less than n, derived from the Mandelbrot set.

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A347928 Triangle read by rows, T(n, k) are the coefficients of the scaled Mandelbrot-Larsen polynomials P(n, x) = 2^(2*n-1)*M(n, x), where M(n, x) are the Mandelbrot-Larsen polynomials; for 0 <= k <= n.

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A052154 Array read by antidiagonals: a(n,k)= coefficient of z^n of p_k(z), where p_k+1(z)=(p_k(z))^2+z, p_1(z)=z.

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A347928 Triangle read by rows, T(n, k) are the coefficients of the scaled Mandelbrot-Larsen polynomials P(n, x) = 2^(2n-1)M(n, x), where M(n, x) are the Mandelbrot-Larsen polynomials; for 0 <= k <= n.