(In reply to
Just an observation by Charlie)
I stopped that program at p=1384433 without having found another answer. I'll try another tack: Take cubes and subtract 1 and divide by 16; if the answer is an integer, I'll check for primality.
10 for Cr=2 to 1000000000
20 C=Cr*Cr*Cr
30 P=(C-1)/16
40 if P=int(P) then P=int(P)
41 :print P
42 :if prmdiv(P)=P then print P,C,Cr::stop:endif
50 :if prmdiv(P)=0 then cancel for:goto 100
60 next
100 end
It's quickly getting to 16 digit values of p and then some, without finding any more primes. The values found in the preceding post are the only ones found.
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Posted by Charlie
on 2020-07-13 15:44:09 |