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A178429 Numbers n such that 10^n - 51 is prime. 2
4, 48, 64, 313, 484, 642, 11950, 15845, 18580, 50929 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

LINKS

Table of n, a(n) for n=1..10.

Makoto Kamada, Near-repdigit numbers of the form AA...AABA.

Makoto Kamada, Prime numbers of the form 99...9949.

Index entries for primes involving repunits.

EXAMPLE

10^4 - 51 = 9949 which is a prime number.

MAPLE

A178429:=n->`if`(isprime(10^n-51), n, NULL): seq(A178429(n), n=1..1000); # Wesley Ivan Hurt, Nov 26 2014

MATHEMATICA

m = 1000; For[n = 1, n < m, If[PrimeQ[10^n - 51], Print[n]]; n++ ]

PROG

(PARI) is(n)=ispseudoprime(10^n-51) \\ Charles R Greathouse IV, Jun 06 2017

CROSSREFS

Cf. A108330, A108328.

Sequence in context: A052105 A010293 A225987 * A242225 A157818 A048608

Adjacent sequences:  A178426 A178427 A178428 * A178430 A178431 A178432

KEYWORD

more,nonn

AUTHOR

Robert Price, Dec 21 2010

EXTENSIONS

a(10) = 50929 found by Robert Price and added by Patrick De Geest, Nov 26 2014

STATUS

approved

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Last modified September 26 05:09 EDT 2017. Contains 292502 sequences.