

A291293


Sequence mod 5 defined by BaldiniEschgfäller coupled dynamical system (f,lambda,alpha) with f(k) = A000203(k)1, lambda(y) = 3y+2 mod 5 for y in Y = {0,1,2,3,4}, and alpha(k) = k mod 5 for k in Omega = {primes}.


2



2, 3, 2, 0, 0, 2, 0, 0, 3, 1, 1, 3, 1, 1, 2, 2, 4, 4, 0, 0, 1, 3, 4, 2, 0, 3, 2, 4, 0, 1, 3, 3, 1, 3, 0, 2, 4, 2, 4, 1, 2, 3, 1, 3, 0, 2, 1, 2, 1, 0, 3, 3, 0, 0, 0, 4, 4, 4, 3, 1, 2, 1, 2, 1, 1, 2, 3, 2, 1, 1, 0, 3, 1, 1, 4, 2, 3, 4, 1, 4, 3, 3, 1, 3, 0
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OFFSET

2,1


COMMENTS

This sequence assumes that the Erdos conjecture is true, that iterating k > sigma(k)1 always reaches a prime (cf. A039654).


LINKS

Table of n, a(n) for n=2..86.
Lucilla Baldini, Josef Eschgfäller, Random functions from coupled dynamical systems, arXiv preprint arXiv:1609.01750 [math.CO], 2016. See Example 3.6.


FORMULA

Let f(k) = A000203(k)1 = sigma(k)  1, lambda(y) = 3y+2 mod 5 for y in Y = {0,1,2,3,4}, and alpha(k) = k mod 5 for k in Omega = {primes}. Here sigma is the sum of divisors function A000203.
Then a(n) for n >= 2 is defined by a(n) = alpha(n) if n in Omega, and otherwise by a(n) = lambda(a(f(n))).


CROSSREFS

Cf. A000203, A039654, A291291, A262684.
Sequence in context: A009108 A016537 A106385 * A259572 A027413 A343230
Adjacent sequences: A291290 A291291 A291292 * A291294 A291295 A291296


KEYWORD

nonn


AUTHOR

N. J. A. Sloane, Aug 30 2017


STATUS

approved



