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A252730 a(n) = P_n(n) with P_0(z) = z+1 and P_n(z) = z + P_{n-1}(z)*(P_{n-1}(z)-z) for n>1. 2
1, 3, 17, 871, 4870849, 483209576974811, 36956045653220845240164417232897, 8498748758632331927648392184620600167779995785955324343380396911247 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,2

LINKS

Alois P. Heinz, Table of n, a(n) for n = 0..10

A. V. Aho and N. J. A. Sloane, Some doubly exponential sequences, Fib. Quart., 11 (1973), 429-437.

MAPLE

p:= proc(n) option remember;

      z-> z+ `if`(n=0, 1, p(n-1)(z)*(p(n-1)(z)-z))

    end:

a:= n-> p(n)(n):

seq(a(n), n=0..8);

MATHEMATICA

p[n_] := p[n] = Function[z, z + If[n == 0, 1, p[n-1][z]*(p[n-1][z] - z)]];

a[n_] := p[n][n];

Table[a[n], {n, 0, 8}] (* Jean-Fran├žois Alcover, Jun 12 2018, from Maple *)

CROSSREFS

Main diagonal of A177888.

Sequence in context: A309060 A270816 A217957 * A225728 A175984 A051710

Adjacent sequences:  A252727 A252728 A252729 * A252731 A252732 A252733

KEYWORD

nonn

AUTHOR

Alois P. Heinz, Dec 20 2014

STATUS

approved

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Last modified May 25 10:33 EDT 2020. Contains 334592 sequences. (Running on oeis4.)