A111349 Numbers n such that the result of swapping the 4th digit and the digit 3 positions from the last digit is prime.

1003, 1004, 1007, 1009, 1010, 1012, 1013, 1015, 1016, 1018, 1019, 1021, 1024, 1025, 1030, 1031, 1040, 1043, 1049, 1051, 1054, 1055, 1060, 1061, 1063, 1070, 1082, 1085, 1088, 1091, 1094, 1096, 1099, 1100, 1105, 1106, 1108, 1112, 1114, 1118, 1123, 1126

Offset: 1

Author

Cino Hilliard, Nov 05 2005

Keywords

• easy
• nonn
• base

Comments

Leading zeros are dropped.

Since these numbers are just digit permutations of the primes the sequence is obviously infinite. - Charles R Greathouse IV, Oct 20 2008

Crossrefs

Cf. A095179, A111347, A111348.

Programs

PARI

swapn(n,d) = \ d is the digit position to swap { local(j,ln,x,s,y,y2,tmp); for(x=10^(d-1),10^(d-1)+n, s = Str(x); ln = length(s); y = eval(Vec(s)); tmp=y[d]; y[d]=y[ln-d+1]; y[ln-d+1]=tmp; y2=0; for(j=1,ln, y2+=y[j]*10^(ln-j); ); if(isprime(y2),print1(x",")) ) }