Thanks @Jean  and @aditya1601 , I will try the windows technique,     regarding aditya’s comment,  the model doesn’t even learn to Add 1 to every number as it is supplied via the current split, I get that the rest of the sequence is ‘disconnected’ but the commonality of every 3-consecutive-numbers sets is not  being  picked up by the model, instead it it give something like    51, 52 …  prediction  = 4.23