Curious prime
 

131071773869

I found this curious prime formed by the concatenation of Mersenne prime 131071 and another 6 digit prime 773869.

Any other prime like that? I mean can you find another prime which is the concatenation of 131071 and another 6 digit prime?

[QUOTE=enzocreti;500979]131071773869

I found this curious prime formed by the concatenation of Mersenne prime 131071 and another 6 digit prime 773869.

Any other prime like that? I mean can you find another prime which is the concatenation of 131071 and another 6 digit prime?[/QUOTE]

11310711000133
11310711000151
11310711000397
11310711000409
11310711000691
11310711000763
11310711000889
11310711000907


to cite a few and a few more [URL="http://factordb.com/index.php?query=11310710000000%2Bx&use=x&perpage=20&format=1&sent=1&PR=1&PRP=1&C=1&U=1&VP=1&EV=1&OD=1&x=1001000"]here[/URL]

curious prime
 

It is not 113...but 1310...

my bad

1310711000099
1310711000171
1310711000381
1310711000483
1310711000723
1310711000777


and many [URL="http://factordb.com/index.php?query=1310710000000%2Bx&use=x&perpage=200&format=1&sent=1&PR=1&PRP=1&C=1&U=1&VP=1&EV=1&OD=1&x=1000500"]more[/URL]

[QUOTE=enzocreti;500979]131071773869

I found this curious prime formed by the concatenation of Mersenne prime 131071 and another 6 digit prime 773869.

Any other prime like that? I mean can you find another prime which is the concatenation of 131071 and another 6 digit prime?[/QUOTE]
There are 4747 such primes.

[QUOTE=Dr Sardonicus;500986]There are 4747 such primes.[/QUOTE]

There are 4572 for 2^19 - 1 = 524287 and 15986936 for 2^31 - 1 = 2147483647. The next Mersenne prime isn't doable (would require looping over > 2e17 primes).

[QUOTE=Dr Sardonicus;500986]There are 4747 such primes.[/QUOTE]Which is itself a two-digit prime concatenated with a two-digit prime. OMG the coincidences are around! The primes are everywhere. I'm beginning to think that might be more than just a few, possibly infinite. :rolleyes: