A065592 Smallest prime beginning with exactly n 9's.

2, 97, 991, 99901, 99991, 9999901, 9999991, 999999929, 9999999929, 99999999907, 999999999937, 9999999999971, 99999999999923, 999999999999947, 9999999999999917, 99999999999999919, 99999999999999997, 9999999999999999919, 99999999999999999931

Offset: 0

Author

Robert G. Wilson v, Nov 28 2001

Keywords

• nonn
• base

Links

• M. F. Hasler, Table of n, a(n) for n = 0..200

Crossrefs

Cf. A037071, A065582, A065584 - A065591.

Programs

Mathematica

fp[n_]:=Select[Join[10*n+{1,7},100*n+Range[1,99,2]],PrimeQ,1]; With[{ns=Table[FromDigits[PadRight[{},n,9]],{n,20}]}, Join[{2}, Flatten[fp/@ns]]] (* Harvey P. Dale, May 12 2012 *)

Extensions

Corrected by Don Reble, Jan 17 2007

Offset corrected by Sean A. Irvine, Sep 06 2023