A092024 a(n) is the smallest number m such that m has n distinct prime divisors and if p is a prime divisor of m then p*m +1 is prime.

2, 6, 354, 210, 43860, 463980, 189583590, 6958972020, 200007607800, 60958204112190, 3337686588286050

Offset

1,1

Links

Table of n, a(n) for n=1..11.

Carlos Rivera, Puzzle 334. Farideh & the 2004 year, The Prime Puzzles & Problems connection.

Example

a(7)=189583590 because 189583590=2*3*5*7*41*97*227, all the seven numbers 2*189583590+1, 3*189583590+1, 5*189583590+1, 7*189583590+1, 41*189583590+1, 97*189583590+1 and 227*189583590+1 are prime numbers and 189583590 is the smallest number m with such property.

Crossrefs

Cf. A092023.

Cf. A112723, A112724.

Sequence in context: A264410 A135014 A321571 * A252741 A069261 A053608

Adjacent sequences: A092021 A092022 A092023 * A092025 A092026 A092027

Keyword

more,nonn

Author

Farideh Firoozbakht, Feb 19 2004

Extensions

a(10) from Michael S. Branicky, Feb 27 2023

a(11) from Michael S. Branicky, Mar 08 2023

Status

approved