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A068815
Primes with a 4 followed by 1's.
2
41, 4111, 41111111111111, 41111111111111111111111111, 4111111111111111111111111111111111111111111111111111111111111111111111111
OFFSET
1,1
COMMENTS
The next term a(6) has 109 digits and is too large to be displayed here.
MATHEMATICA
Select[Table[FromDigits[PadRight[{4}, n, 1]], {n, 1000}], PrimeQ] (* Harvey P. Dale, Sep 15 2019 *)
PROG
(PARI) for(n=1, 200, if(isprime(4*10^n+(10^(n)-1)/9)==1, print1(4*10^n+(10^(n)-1)/9, ", ")))
CROSSREFS
Cf. A002275, A056706 (corresponding values of n).
Sequence in context: A233015 A282054 A107690 * A093174 A280677 A209104
KEYWORD
nonn,base
AUTHOR
Amarnath Murthy, Mar 07 2002
EXTENSIONS
More terms from Benoit Cloitre, Mar 09 2002
STATUS
approved