found before ?

[science_man_88]

mod 30 the 9,1,1,3 seem to convert to 29,1,11,13

[science_man_88]

mod 20 give numbers ending in 9,1,1,3 but seems to change between 9,11,1,3

and things like 19,1,11,13

[CRGreathouse]

So what are the probabilities?

I calculated the actual occurrences up to 5 billion: 57.0%. This is pretty close to my number working mod 30. I suppose if I wanted to improve I could work mod 210... mod 20 is obviously worse than mod 30, and probably not better than mod 10.

[science_man_88]

mod 210 seems to keep the last digit accurate from what i can tell though that may have to be double checked.

[CRGreathouse]

Originally Posted by science_man_88

mod 210 seems to keep the last digit accurate from what i can tell though that may have to be double checked.

So... what are the probabilities?

I'm looking for "there are A possibilities out of B mod 30 for two digits preceding ,9,1,1,3, and C possibilities out of D mod 30 for the two digits following ,9,1,1,3, giving a total probability x% that ,9,1,1,3, is followed or preceded by 7,9."

Of course you could work mod 210 if you prefer.

[science_man_88]

Originally Posted by kar_bon

A line of PARI-code and some digits won't understand anyone without a (very) closer look!

didn't know pari code was watching anyone