Generalisation for all numbers n, (n+1), (n+2) etc.
Consider small numbers of terms:
(n^4+n^2+1) = (n^2-n+1)(n^2+n+1)
(n^4+n^2+1)((n+1)^4+(n+1)^2+1) = (n^2-n+1)(n^2+n+1)^2(n^2+3n+3)
(n^4+n^2+1)((n+1)^4+(n+1)^2+1)((n+2)^4+(n+2)^2+1) =
(n^2-n+1)(n^2+n+1)^2(n^2+3n+3)^2(n^2+5n+7)
(n^4+n^2+1)((n+1)^4+(n+1)^2+1)((n+2)^4+(n+2)^2+1)((n+3)^4+(n+3)^2+1) =
(n^2-n+1)(n^2+n+1)^2(n^2+3n+3)^2(n^2+5n+7)^2(n^2+7n+13)
(n^4+n^2+1)((n+1)^4+(n+1)^2+1)((n+2)^4+(n+2)^2+1)((n+3)^4+(n+3)^2+1)((n+4)^4+(n+4)^2+1) =
(n^2-n+1)(n^2+n+1)^2(n^2+3n+3)^2(n^2+5n+7)^2(n^2+7n+13)^2(n^2+9n+21)
The intermediate expressions, except for the first and last, form a series of squares, so the problem is equivalent to (n^2-n+1)(n^2+(2k-1)n+(k^2-k+1)) = m^2 with {n,k} in the positive integers.
But there are no such solutions:
{{k == -5, m == 7, n == 3}, {k == -3, m == 3, n == 2}, {k == -1, m == 1, n == 1}, {k == 0, m == 1, n == 0}, {k == 0, m == 1, n == 1}, {k == 0, m == 3, n == -1}, {k == 0, m == 3, n == 2}, {k == 0, m == 7, n == -2}, {k == 0, m == 7, n == 3}, {k == 1, m == 1, n == 0}, {k == 3, m == 3, n == -1}, {k == 5, m == 7, n == -2}}
Edited on September 27, 2020, 9:33 am
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Posted by broll
on 2020-09-27 09:31:56 |