A	B	C
D		E
F	G	H

The letters A-H are different digits from 1 to 9.

Read from left to right and top down, the four numbers formed are primes.

There is not just one solution. (Flipping along the diagonal A-H does not present a different solution).

Suppose "0" is allowed, and A cannot have that value, what other unique solutions are available?

(In reply to re(2): Extensive === a powerful tool by brianjn)

Brian, I "met" the owner about a year ago. By that time I found some bugs in his solving program and he promptly corrected. Rainer is very receptive to any comments about possible errors. He has an edited book with many crossnumbers (I bought one) and some newspapers publish regularly new problems he creates.

I used his site to solve a problem submitted here, a matrix 4x4 formed by 8 squares of 4 digits each and also, a matrix 5x5 formed by 10 squares of 5 digits each.

Another problem I solved there (I already had solved it by reasoning) is the crypt "I * MENSA = ZZZZZZ". And others.

However, solving your problem the program didnŽt found all the solutions listed by Charlie. Since you can follow the iterations which are being made by the program, and also see "the solutions found till now", it looks that there is another bug in it.

IŽll write him asking what possibly is going wrong when solving your particular problem. 

And youŽre absolutely right about bookmarking it. Besides IŽm registered in it so I can use and create problems of this kind.

Posted by pcbouhid on 2009-07-11 22:47:25