

A256508


Lexicographically earliest sequence of distinct terms, with a unique fixed point, such that a^n(n)=n, for any n>0 (where a^n denotes the nth iterate of a).


2



1, 4, 6, 2, 10, 9, 14, 12, 3, 15, 22, 8, 26, 21, 20, 18, 34, 16, 38, 25, 28, 33, 46, 27, 5, 39, 30, 35, 58, 24, 62, 36, 44, 51, 42, 32, 74, 57, 52, 45, 82, 49, 86, 55, 50, 69, 94, 54, 7, 60, 68, 65, 106, 48, 66, 63, 76, 87, 118, 70, 122, 93, 77, 72, 78, 88
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OFFSET

1,2


COMMENTS

The unique fixed point constraint ensures that this sequence differs from A000027.
This is a permutation of the natural numbers, with inverse A256513.
The length of the orbit of n is a prime divisor of n, for any n>1.
GCD(n, a(n))>1, for any n>1.


LINKS

Paul Tek, Table of n, a(n) for n = 1..10000
Paul Tek, Perl program for this sequence
Wikipedia, Iterated function
Index entries for sequences that are permutations of the natural numbers


EXAMPLE

a^1(1)=a(1)=1.
a^2(2)=a(a(2))=a(4)=2.
a^3(3)=a(a(a(3)))=a(a(6))=a(9)=3.


PROG

(Perl) See Links section.


CROSSREFS

Cf. A256513.
Sequence in context: A251561 A159193 A118967 * A059030 A066984 A241341
Adjacent sequences: A256505 A256506 A256507 * A256509 A256510 A256511


KEYWORD

nonn,nice


AUTHOR

Paul Tek, Mar 31 2015


STATUS

approved



