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

Author

Jason Earls, Dec 20 2002

Keywords

• base
• nonn
• nice

Comments

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

Crossrefs

Cf. A000215.

Programs

Mathematica

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