A335363 The smallest prime and start of a run of exactly n primes that remain prime after each digit is replaced by its square.

2, 19, 13, 131, 2111, 12815137, 103723971119

Offset

1,1

Comments

a(7) > 4294967296.

Terms in A020449 are not terms of this sequence. - Chai Wah Wu, Jun 18 2020

a(8) > 10^13, if it exists. - Giovanni Resta, Jun 21 2020

Links

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

Example

a(3)=13 because 13 -> 19 -> 181 are primes and 1641 is composite.

Crossrefs

Cf. A020449, A068492.

Sequence in context: A128361 A096481 A376920 * A176618 A356477 A153653

Adjacent sequences: A335360 A335361 A335362 * A335364 A335365 A335366

Keyword

nonn,base,more

Author

Carlos Rivera, Jun 10 2020

Extensions

a(7) from Giovanni Resta, Jun 20 2020

Status

approved