You can put this solution on YOUR website! Start with 1.
Multiply by negative 1 to get -1.
Multiply by negative 1 and add 1 to get 2.
Multiply by negative 1 to get -2.
Multiply by negative 1 and add 1 to get 3.
That looks like a pattern, now continue it.
Multiply by negative 1 to get -3.
Multiply by negative 1 and add 1 to get 4. is the next term.