A078726 Fermat numbers 2^(2^n) + 1 with digits sorted in increasing order and zeros suppressed.

3, 5, 17, 257, 35567, 2244677999, 111344445566777789, 111222233333334444445666666777788899, 111111222223333333344444455555555566666666777777778888888999999999999

Offset

0,1

Comments

The 0, 1, 2, 3, 5 and 7 terms of this sequence are primes. Are there any more?

Links

Table of n, a(n) for n=0..8.

Mathematica

Table[FromDigits[Sort[IntegerDigits[2^2^n+1]]/.(0->Nothing)], {n, 0, 10}] (* Harvey P. Dale, Apr 11 2021 *)

Crossrefs

Cf. A000215.

Sequence in context: A260377 A056130 A273871 * A019434 A164307 A125045

Adjacent sequences: A078723 A078724 A078725 * A078727 A078728 A078729

Keyword

base,nonn,nice

Author

Jason Earls, Dec 20 2002

Status

approved