A124248 Numbers n such that n!!+2^n is prime.

0, 1, 3, 5, 7, 15, 23, 41, 57, 71, 81, 121, 139, 375, 623, 1143, 2629, 3011, 3631, 4895, 5237, 9569, 10179, 14179, 16883, 33129

Offset

1,3

Comments

a(27) > 50000. - Robert Price, Sep 04 2015

Links

Table of n, a(n) for n=1..26.

Example

5 is in the sequence because 5!!+2^5=47 is prime.

Mathematica

Select[Range[0, 50000], PrimeQ[#!! + 2^#] &] (* Robert Price, Sep 04 2015 *)

Crossrefs

Cf. A124249.

Sequence in context: A071169 A172235 A163979 * A029514 A061950 A166093

Adjacent sequences: A124245 A124246 A124247 * A124249 A124250 A124251

Keyword

more,nonn

Author

Farideh Firoozbakht, Nov 27 2006, corrected Nov 28 2006

Extensions

a(19)-a(26) from Robert Price, Sep 04 2015

Status

approved