The OEIS is supported by the many generous donors to the OEIS Foundation.

 Year-end appeal: Please make a donation to the OEIS Foundation to support ongoing development and maintenance of the OEIS. We are now in our 59th year, we have over 358,000 sequences, and we’ve crossed 10,300 citations (which often say “discovered thanks to the OEIS”). Other ways to Give
 Hints (Greetings from The On-Line Encyclopedia of Integer Sequences!)
 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. 2
 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 (list; table; graph; refs; listen; history; text; internal format)
 OFFSET 1,13 COMMENTS 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. LINKS R. P. Munafo, Mu-Ency - The Encyclopedia of the Mandelbrot Set Eric Weisstein's World of Mathematics, Mandelbrot Set FORMULA 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. EXAMPLE 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, ... MATHEMATICA 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 *) CROSSREFS Cf. A000108. Cf. A137560, which gives the same array read by rows. [From Robert Munafo, Dec 12 2009] Sequence in context: A113652 A106139 A350871 * A039977 A197548 A029403 Adjacent sequences: A052151 A052152 A052153 * A052155 A052156 A052157 KEYWORD nice,nonn,tabl,easy AUTHOR Klaus Strassburger (strass(AT)ddfi.uni-duesseldorf.de), Jan 24 2000 STATUS approved

Lookup | Welcome | Wiki | Register | Music | Plot 2 | Demos | Index | Browse | More | WebCam
Contribute new seq. or comment | Format | Style Sheet | Transforms | Superseeker | Recents
The OEIS Community | Maintained by The OEIS Foundation Inc.

Last modified December 7 05:22 EST 2022. Contains 358649 sequences. (Running on oeis4.)