A concordant form is an integer triple where
(1)
|
with
and
integers. Examples include
(2)
|
Dickson (2005) states that C. H. Brooks and S. Watson found in The Ladies' and Gentlemen's Diary (1857) that and
can be simultaneously squares for
only for 1, 7, 10, 11, 17, 20, 22, 23, 24, 27, 30,
31, 34, 41, 42, 45, 49, 50, 52, 57, 58, 59, 60, 61, 68, 71, 72, 74, 76, 77, 79, 82,
85, 86, 90, 92, 93, 94, 97, 99, and 100 (which evidently omits 47, 53, and 83 from
above). The list of concordant primes less than 1000 is now complete with the possible
exception of the 16 primes 103, 131, 191, 223, 271, 311, 431, 439, 443, 593, 607,
641, 743, 821, 929, and 971.