A344424 Numbers k such that A344423(k) is prime.

3, 54, 58, 64, 70, 253, 438, 4255, 8770

Offset

1,1

Comments

a(10) > 10000. - Hugo Pfoertner, May 19 2021

Links

Table of n, a(n) for n=1..9.

Example

A344423(3) = 100111001 is prime, so 3 is a term of the sequence.

Prog

(PARI) is(n) = ispseudoprime(10^(2*n+2) + 111*10^n + 1)

Crossrefs

Cf. A070247, A100580, A344423.

Sequence in context: A208631 A093164 A092448 * A045481 A275566 A068380

Adjacent sequences: A344421 A344422 A344423 * A344425 A344426 A344427

Keyword

nonn,hard,more

Author

Felix Fröhlich, May 18 2021

Extensions

a(9) from Hugo Pfoertner, May 19 2021

Status

approved