A171045 -id:A171045 - cp's OEIS frontend

A180549 Primes that become a different prime under the mapping 4 <=> 8.

43, 83, 241, 281, 349, 389, 409, 421, 439, 443, 457, 463, 547, 587, 643, 683, 809, 821, 839, 857, 863, 883, 1249, 1289, 1423, 1471, 1487, 1543, 1583, 1747, 1787, 1823, 1847, 1871, 2341, 2381, 2437, 2447, 2647, 2687, 2749, 2789, 2837, 2887, 3049, 3089, 3433

Offset: 1

Zak Seidov and Robert G. Wilson v, Sep 09 2010

Robert Israel, Table of n, a(n) for n = 1..10000
Index to Primes, Primes that become a different prime under some mapping.

Cf. A171045, A175791, A180517 thru A180559, A175789, A180560, A180561.

filter:= proc(n) local L,Lp,i;
  if not isprime(n) then return false fi;
  L:= convert(n,base,10);
  Lp:= subs({4=8,8=4},L);
  if L = Lp then return false fi;
  isprime(add(Lp[i]*10^(i-1),i=1..nops(L)));
end proc:
select(filter, [seq(i,i=3..10000,2)]); # Robert Israel, Nov 27 2019

fQ[n_] := Block[{id = IntegerDigits@n}, (MemberQ[id, 4] || MemberQ[id, 8]) && PrimeQ[ FromDigits[ id /. {4 -> 8, 8 -> 4}] ]]; Select[ Prime@ Range@ 490, fQ]

A222243 In the number n, replace all (decimal) digits '4' with '8' and vice versa.

Original entry on oeis.org

0, 1, 2, 3, 8, 5, 6, 7, 4, 9, 10, 11, 12, 13, 18, 15, 16, 17, 14, 19, 20, 21, 22, 23, 28, 25, 26, 27, 24, 29, 30, 31, 32, 33, 38, 35, 36, 37, 34, 39, 80, 81, 82, 83, 88, 85, 86, 87, 84, 89, 50, 51, 52, 53, 58, 55, 56, 57, 54, 59, 60, 61, 62, 63, 68, 65, 66, 67, 64, 69, 70, 71, 72, 73, 78, 75

Offset: 0

M. F. Hasler, Feb 13 2013

The map which is applied to primes in A171045.

Vincenzo Librandi, Table of n, a(n) for n = 0..1000

Cf. A222210-A222254; A171013-A171016, A175770, A171018-A171057.

a[n_]:= IntegerDigits[n]/.{4->8, 8->4} // FromDigits; Table[a[n], {n, 0, 80}] (* Vincenzo Librandi, Jul 31 2013 *)

A222243(n,d=[0, 1, 2, 3, 8, 5, 6, 7, 4, 9])={sum(i=1,#n=digits(n),d[n[i]+1]*10^(#n-i),!n*d[1])} \\ N.B.: digits(0)=[] in PARI (v.2.6)

cp's OEIS Frontend

A180549 Primes that become a different prime under the mapping 4 <=> 8.

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