A175770 - OEIS

A175770

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

%I #15 Feb 02 2021 02:09:13

%S 2,1,5,7,33,31,37,39,21,29,13,17,43,41,47,51,59,63,67,73,71,79,81,89,

%T 97,303,301,307,309,331,327,313,317,319,349,353,357,361,367,371,379,

%U 383,393,391,397,399,233,221,227,229,211,219,243,253,257,261,269,273,277

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

%H Vincenzo Librandi, <a href="/A175770/b175770.txt">Table of n, a(n) for n = 1..1000</a>

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

%o (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

%o (Python)

%o from sympy import prime

%o def a(n):

%o return int(str(prime(n)).translate({ord('1'):ord('3'), ord('3'):ord('1')}))

%o print([a(n) for n in range(1, 60)]) # _Michael S. Branicky_, Feb 01 2021

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

%K nonn,base,easy

%O 1,1

%A _Vincenzo Librandi_, Sep 01 2010

%E Corrected by _D. S. McNeil_ and _R. J. Mathar_, Sep 02 2010