A171037 In the sequence of prime numbers, replace all the '7' digits with '3' and vice versa.

2, 7, 5, 3, 11, 17, 13, 19, 27, 29, 71, 73, 41, 47, 43, 57, 59, 61, 63, 31, 37, 39, 87, 89, 93, 101, 107, 103, 109, 117, 123, 171, 173, 179, 149, 151, 153, 167, 163, 137, 139, 181, 191, 197, 193, 199, 211, 227, 223, 229, 277, 279, 241, 251, 253, 267

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

pq[n_]:=Module[{idn=IntegerDigits[n]},FromDigits[idn/.{7->p,3->q}/.{p->3,q->7}]]; pq/@Prime[Range[60]] (* Harvey P. Dale, Dec 11 2012 *)

PARI

a(n)=my(v=[0,1,2,7,4,5,6,3,8,9]);subst(Pol(apply(k->v[k+1], digits(prime(n)))),'x,10) \\ Charles R Greathouse IV, Jul 25 2013