A290045 Primes in A290044.

7, 41, 176075177, 49127973630377

Offset

1,1

Comments

For n < 20, A290044(n) are prime when n = {2, 3, 9, 13}.

For n >= 20, 19|A290044(n). Therefore there are only 4 terms in this sequence.

Links

Table of n, a(n) for n=1..4.

Example

41 = |0!! - 2!! + 4!! - 6!!| is prime.

Mathematica

Select[Table[Abs@ Sum[(-1)^k*(2 k)!!, {k, 0, n}], {n, 0, 60}], PrimeQ] (* Michael De Vlieger, Jul 19 2017 *)

Crossrefs

Cf. A006882, A071828, A290044.

Sequence in context: A144747 A176090 A183064 * A188066 A225327 A102532

Adjacent sequences: A290042 A290043 A290044 * A290046 A290047 A290048

Keyword

nonn,fini,full

Author

XU Pingya, Jul 19 2017

Status

approved