OFFSET
1,1
COMMENTS
Number of terms of n digits: 4, 21, 16, 8, 9, 8, 2, 8, 7, 3, 4, 5, 2, 2, 4, 0, 3, 4, 2, 3, 2, 2, 4, 1, 0, ..., . - Robert G. Wilson v, May 29 2011
LINKS
Charles R Greathouse IV, Table of n, a(n) for n = 1..260
EXAMPLE
4441 is a member where a=1 and b = 4.
MATHEMATICA
f[n_] := Select[ Union@ Flatten@ Table[ FromDigits@ Join[ Table[b, {n - 1}], {a}], {b, 9}, {a, {1, 3, 7, 9}}], PrimeQ]; f[1] = {2, 3, 5, 7}; Array[f, 5] // Flatten (* Robert G. Wilson v, May 29 2011 *)
PROG
(PARI) print1("2, 3, 5, 7"); for(n=2, 20, forstep(k=10^n\9-1, 10^n-9, 10^n\9-1, for(m=k+1, k+9, if(isprime(m), print1(", "m))))) \\ Charles R Greathouse IV, May 29 2011
CROSSREFS
KEYWORD
nonn,base,easy
AUTHOR
Amarnath Murthy, Jun 23 2001
EXTENSIONS
More terms from Jason Earls, Jun 26 2001
Corrected and extended by Dean Hickerson, Jul 10 2001
STATUS
approved