|
Search: id:A111349
|
|
|
| A111349 |
|
Numbers n such that the result of swapping the 4-th digit and the digit 3 positions from the last digit is prime. |
|
+0
3
|
|
| 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
(list; graph; listen)
|
|
|
OFFSET
|
1,1
|
|
|
COMMENT
|
Leading zeros are dropped.
Since these numbers are just digit permutations of the primes the sequence is obviously infinite. - Charles Greathouse, Oct 20 2008
|
|
PROGRAM
|
(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", ")) ) }
|
|
CROSSREFS
|
Cf. A095179, A111347, A111348.
Sequence in context: A097659 A143906 A139105 this_sequence A013686 A067918 A092924
Adjacent sequences: A111346 A111347 A111348 this_sequence A111350 A111351 A111352
|
|
KEYWORD
|
easy,nonn,base
|
|
AUTHOR
|
Cino Hilliard (hillcino368(AT)gmail.com), Nov 05 2005
|
|
|
Search completed in 0.002 seconds
|
