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A125840 Two-sided multiplicative pointer primes. 2
1123, 21911, 3116111, 11413111, 12111331, 14111311, 316111111, 1111131821, 11112119111, 11161211111, 111161111311, 111211231111, 1111112111191, 2111191111111, 11131211113111, 21111121126111, 31111127111111, 111211151611111, 111211222111123, 121132111712111 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

Following the definition of multiplicative pointer primes (A089823), I call a prime p a two-sided multiplicative pointer prime if previous_prime(p)=p-P and next_prime(p)=p+P where P is the product of the digits of p.

LINKS

Giovanni Resta, Table of n, a(n) for n = 1..59 (terms < 10^19)

Carlos Rivera and Joseph L. Pe, Pointer primes.

EXAMPLE

11112119111 is in the sequence because previous_prime(11112119111)

= 11112119111 - 1*1*1*1*2*1*1*9*1*1*1 and next_prime(11112119111)

= 11112119111 + 1*1*1*1*2*1*1*9*1*1*1.

MATHEMATICA

Do[p=Prime[m]; P=Apply[Times, IntegerDigits[p]]; If[Prime[m-1]== p-P&&Prime[m+1]==p+P, Print[p]], {m, 2, 140000000}]

CROSSREFS

Cf. A089823, A125841, A127836.

Sequence in context: A105310 A200072 A261264 * A069984 A104285 A260898

Adjacent sequences:  A125837 A125838 A125839 * A125841 A125842 A125843

KEYWORD

hard,base,nonn

AUTHOR

Farideh Firoozbakht, Feb 02 2007

EXTENSIONS

a(9)-a(20) from Donovan Johnson, Oct 21 2013

STATUS

approved

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Last modified October 14 16:48 EDT 2019. Contains 328022 sequences. (Running on oeis4.)