Question

how many terms of the sequence -6,-11/2,-5.... must be taken to make the sum -25..?​

Answer 1

Answer:

Is there any series of primes A=(a1,a2,...an) s.t:

a21+a22+...+a2n=S

And there is a series B=(b1,...bn) which every bi∈A (Yes, it might be bi=bj when i≠j).

And satisfy b21+b22+...+b2n=S

Note: ai≠aj when i≠j but not in B.

One more rule, B cannot be a A in other/same order. Wihch means must be in B at least two element in B that are equal.

EDIT: calrification:

I want to find a group of n different primes, that a the sum of their squares will be equal to the sum of square of another group of n primes, which are subset of the first one, for example:

Lets take 3, 5 and 11. Is there any 3 elements you can take from that group (not all of them) so their square in sum will be 32+52+112=155? A try can be (11,11,3) but 112+112+32≠155