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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 (list; graph; refs; listen; history; text; internal format)
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

Table of n, a(n) for n=1..17.

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

Cf. A007918, A089823, A091628, A091629, A091630, A091632.

Sequence in context: A146224 A287306 A142066 * A244767 A146421 A093401

Adjacent sequences:  A091628 A091629 A091630 * A091632 A091633 A091634

KEYWORD

base,easy,nonn

AUTHOR

Enoch Haga, Jan 24 2004

EXTENSIONS

Edited and extended by Ray Chandler, Feb 07 2004

STATUS

approved

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Last modified October 16 23:30 EDT 2019. Contains 328103 sequences. (Running on oeis4.)