Prove that 3^105+4^105 is divisible by 13*49*181*379 but is not divisible by either 5 or 11.
a=3^105+4^105
OK
?a
1645504557321331278892507061310792365037268911602846475476455267
OK
?a@13
0
OK
?a@49
0
OK
?a@181
0
OK
?a@379
0
OK
b=13*49*181*379
OK
?b
43697563
OK
?a@b
0
OK
?a@11
2
OK
and of course it goes without saying, but I'll say it anyway, that a number ending in 7 is not divisible by 5.
Edited on August 16, 2011, 9:11 am

Posted by Charlie
on 20110816 09:10:14 