A175770 In the sequence of prime numbers, replace all the '3' digits with '1' and vice versa.

2, 1, 5, 7, 33, 31, 37, 39, 21, 29, 13, 17, 43, 41, 47, 51, 59, 63, 67, 73, 71, 79, 81, 89, 97, 303, 301, 307, 309, 331, 327, 313, 317, 319, 349, 353, 357, 361, 367, 371, 379, 383, 393, 391, 397, 399, 233, 221, 227, 229, 211, 219, 243, 253, 257, 261, 269, 273, 277

Offset: 1

Author

Vincenzo Librandi, Sep 01 2010

Keywords

• nonn
• base
• easy

Links

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

Crossrefs

Cf. A000040 (the prime numbers), A171013-A171016, A171018-A171057.

Programs

Mathematica

FromDigits[IntegerDigits[#]/.{3->p, 1->q}/.{p->1, q->3}]&/@Prime[Range[60]] (* Vincenzo Librandi, Jul 29 2013 *)

PARI

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

Python

from sympy import prime
def a(n):
  return int(str(prime(n)).translate({ord('1'):ord('3'), ord('3'):ord('1')}))
print([a(n) for n in range(1, 60)]) # Michael S. Branicky, Feb 01 2021

Extensions

Corrected by D. S. McNeil and R. J. Mathar, Sep 02 2010