OFFSET
1,1
REFERENCES
C. Caldwell and H. Dubner, "Journal of Recreational Mathematics", Volume 28, No. 1, 1996-97, pp. 1-9.
LINKS
Patrick De Geest, World!Of Numbers, Palindromic Wing Primes (PWP's)
Makoto Kamada, Prime numbers of the form 99...99499...99
FORMULA
a(n) = (A077782(n)-1)/2.
MATHEMATICA
Do[If[PrimeQ[10^(2n + 1) - 5*10^n - 1], Print[n]], {n, 3000}]
PROG
(PARI) is(n)=ispseudoprime(10^(2*n+1)-5*10^n-1) \\ Charles R Greathouse IV, Jun 13 2017
CROSSREFS
KEYWORD
nonn,base
AUTHOR
Ray Chandler, Dec 28 2010
STATUS
approved