Select integer x and triangular number y such that 8y=3x^4-2x^2-1.

Prove that y is divisible by 28 - or find a counter-example.

(In reply to

re: SOLUTION +some add-ons by broll)

Mr Broll, Esq

It is* implicit* indeed, but passed unnoticed.

I liked this problem very much - it forced me to go down the memory lane all the way to Recursion Avenue..

Cheers!