Who called from 7184383776

I get calls from this number and they don't say a word.

i keep missing calls from this number and they don't leave a message

i keep getting calls from this number too.  And again they don't say anything...

It is someone trying to help with Math. Weird? They took me off their list.

I too have been getting phone calls from them as well along with
718 438 3743,
718 438 3744,
718 438 3746

Same thing, no message left but they seem to call 3 times a day sometimes.