A171018 In the sequence of prime numbers, replace all the '3' digits with '2' and vice versa.

3, 2, 5, 7, 11, 12, 17, 19, 32, 39, 21, 27, 41, 42, 47, 52, 59, 61, 67, 71, 72, 79, 82, 89, 97, 101, 102, 107, 109, 112, 137, 121, 127, 129, 149, 151, 157, 162, 167, 172, 179, 181, 191, 192, 197, 199, 311, 332, 337, 339, 322, 329, 341, 351, 357, 362

Offset: 1

Author

N. J. A. Sloane and Vincenzo Librandi, Sep 04 2010

Keywords

• nonn
• base
• easy

Links

• Vincenzo Librandi, Table of n, a(n) for n = 1..1000

Programs

Mathematica

f[n_]:=FromDigits[(IntegerDigits[n]/.{2->a,3->b}) /.{a->3,b->2}]; f/@Prime[Range[80]]  (* Harvey P. Dale, Apr 01 2011 *)

PARI

a(n)=my(v=[0,1,3,2,4,5,6,7,8,9]);apply(k->v[k+1],digits(prime(n))) \\ Charles R Greathouse IV, Jul 16 2013