

A257793


Lexicographically earliest injective sequence such that a(n)+a(a(n)) is prime


1



1, 3, 2, 5, 6, 7, 10, 9, 8, 13, 12, 11, 16, 15, 14, 21, 18, 19, 22, 23, 20, 25, 24, 29, 28, 27, 26, 31, 30, 37, 36, 33, 34, 39, 38, 35, 42, 41, 40, 43, 48, 47, 46, 45, 44, 51, 50, 49, 52, 53, 56, 55, 54, 59, 58, 57, 70, 69, 68, 61, 66, 63, 64, 67, 71, 73, 72
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OFFSET

1,2


COMMENTS

"Lexicographically earliest injective sequence" means that a(n+1) is the least positive integer not occurring earlier with the given property.


LINKS

Lars Blomberg, Table of n, a(n) for n = 1..10000
E. Angelini, a(n)+a(a(n)) is prime, Seqfan (Apr 11 2015)


EXAMPLE

a(1)=1, a(a(1))=1, 1+1=2 which is prime.
a(7)=10, a(a(7))=a(10)=13, 10+13=23 which is prime.


CROSSREFS

Sequence in context: A154437 A305428 A269376 * A302717 A277820 A277680
Adjacent sequences: A257790 A257791 A257792 * A257794 A257795 A257796


KEYWORD

nonn


AUTHOR

Eric Angelini and Lars Blomberg, May 11 2015


STATUS

approved



