A254380 2^2*3^3*...*a(n)^a(n) + 1 is prime, a(n) is prime, a(n)>a(n-1), and a(n) is minimal.

2, 3, 19, 11251

Offset

1,1

Comments

Observation: a(2)..a(4) coincide with a(1)..a(3) from A191623. - Omar E. Pol, Jan 30 2015

Links

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

Chris K. Caldwell and G. L. Honaker, Jr. Prime Curios!

Example

a(1)=2 because 2 and (2^2)+1=5 are prime.
a(2)=3 because 3 and (2^2*3^3)+1=109 are prime.
a(3)=19 because 19 and (2^2*3^3*19^19)+1=213669322811313867625389733 are prime, and this did not work for either 5, 7, 11, 13.

Crossrefs

Cf. A000040, A051674, A191623.

Sequence in context: A014547 A066735 A232498 * A099069 A038584 A108022

Adjacent sequences: A254377 A254378 A254379 * A254381 A254382 A254383

Keyword

nonn,hard,more

Author

G. L. Honaker, Jr., Jan 29 2015

Extensions

a(4) found by Chris K. Caldwell

Status

approved