John Conway's "look and say" sequence has no digits other than 1, 2, and 3 in it, unless the seed number contains such a digit or a run of more than three of the same digit. A degenerate sequence appears with the seed of 22.
Answer: Paul Erdős
Erdős published at least 1,525 mathematical papers during his lifetime. He engaged more than 500 collaborators and devoted most of his time to mathematics up until his death in 1996 at the age of 83 years old.
Answer: No, it's not!
Adding up the divisors of 36: 1 + 2 + 3 + 4 + 6 + 9 + 12 + 18 = 55
Answer: 4 trivial factors.
The positive +1 and +N and the negative -1 and -N.
Answer: 180 degrees
The angles of a triangle always sum to 180 degrees.