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A091631
Next prime associated with A091628.
5
29, 227, 2237, 22229, 222247, 2222239, 22222253, 222222227, 2222222243, 22222222273, 222222222301, 2222222222243, 22222222222229, 222222222222227, 2222222222222281, 22222222222222301, 222222222222222281
OFFSET
1,1
COMMENTS
Sequence arising in Farideh Firoozbakht's solution to Prime Puzzle 251 - 23 is the only pointer prime (A089823) not containing the digit "1".
The monotonically increasing value of successive product of digits (A091629) strongly suggests that in successive n the digit 1 must be present.
LINKS
Carlos Rivera's Prime Puzzles and Problems Connection, Puzzle 251, Pointer primes
FORMULA
a(n) = A007918(A091628(n)+1).
EXAMPLE
a(1) = nextprime(23+1) = 29.
PROG
(PARI) a(n) = nextprime((10^(n+1) - 1)/9*2 + 2); \\ Michel Marcus, Mar 18 2018
CROSSREFS
KEYWORD
base,easy,nonn
AUTHOR
Enoch Haga, Jan 24 2004
EXTENSIONS
Edited and extended by Ray Chandler, Feb 07 2004
STATUS
approved