A162018 Numbers n for which 2^^n != 2^2^n (mod n); for the "^^" notation see A092188.

7, 9, 11, 13, 19, 21, 22, 23, 25, 27, 29, 31, 33, 35, 37, 38, 39, 41, 45, 47, 49, 50, 53, 54, 55, 57, 59, 61, 62, 63, 65, 66, 67, 69, 71, 73, 74, 75, 77, 79, 81, 82, 83, 86, 87, 89, 91, 92, 93, 94, 95, 97, 98, 99, 101, 103, 105, 106, 107, 108, 109, 110, 111, 113, 114, 115

Offset

1,1

Links

Table of n, a(n) for n=1..66.

Robert Munafo, 2^^N == 2^(2^N) mod N

Example

7 is in the sequence because 2^2^7 = 2^128 == 4 mod 7, but 2^^7 = 2^2^2^2^2^2^2 == 2 mod 7.

Crossrefs

Cf. A092188, A162002, A014221

Sequence in context: A023389 A248963 A221636 * A055741 A103621 A081239

Adjacent sequences: A162015 A162016 A162017 * A162019 A162020 A162021

Keyword

easy,nonn

Author

Robert Munafo, Jun 24 2009

Status

approved