A171025 - OEIS

%I #9 Mar 31 2017 20:28:02

%S 5,3,2,7,11,13,17,19,53,59,31,37,41,43,47,23,29,61,67,71,73,79,83,89,

%T 97,101,103,107,109,113,157,131,137,139,149,121,127,163,167,173,179,

%U 181,191,193,197,199,511,553,557,559,533,539,541,521,527,563

%N In the sequence of prime numbers, replace all the '5' digits with '2' and vice versa.

%H Vincenzo Librandi, <a href="/A171025/b171025.txt">Table of n, a(n) for n = 1..1000</a>

%t FromDigits[IntegerDigits[#]/.{5->p, 2->q}/.{p->2, q->5}]&/@Prime[Range[100]] (* _Vincenzo Librandi_, Apr 07 2013 *)

%o (PARI) a(n)=my(v=[0,1,5,3,4,2,6,7,8,9]);subst(Pol(apply(k->v[k+1], digits(prime(n)))),'x,10) \\ _Charles R Greathouse IV_, Jul 16 2013

%K nonn,base,easy

%O 1,1

%A _N. J. A. Sloane_ and _Vincenzo Librandi_, Sep 04 2010