A257793 Lexicographically earliest injective sequence such that a(n)+a(a(n)) is prime

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

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 * A376890 A302717 A277820

Adjacent sequences: A257790 A257791 A257792 * A257794 A257795 A257796

Keyword

nonn

Author

Eric Angelini and Lars Blomberg, May 11 2015

Status

approved