A303091 Primes of the form 5^k + 2*k.

7, 29, 131, 78139, 3814697265661, 7450580596923828179, 4336808689942017736029811203479766845703247

Offset

1,1

Comments

a(8) has 504 digits and is too large to be included.

Links

Table of n, a(n) for n=1..7.

Example

7 is a member of the sequence because 7 is a prime and 5^1 + 2*1 = 7.
29 is a member of the sequence because 29 is a prime and 5^2 + 2*2 = 29.
131 is a member of the sequence because 131 is a prime and 5^3 + 2*3 = 131.

Maple

a:=k->`if`(isprime(5^k+2*k), 5^k+2*k, NULL): seq(a(k), k=1..1500);

Mathematica

Select[Table[5^k+2k, {k, 80}], PrimeQ] (* Harvey P. Dale, Jul 11 2021 *)

Prog

(GAP) Filtered(List([1..700], k ->5^k+2*k), IsPrime);

Crossrefs

Cf. A299642, A299643, A297663, A303090.

Sequence in context: A126394 A252832 A074468 * A333887 A179599 A266473

Adjacent sequences: A303088 A303089 A303090 * A303092 A303093 A303094

Keyword

nonn

Author

Muniru A Asiru, Apr 18 2018

Status

approved