# A simple dare from Columbia

Yesterday a colleague of mine from Columbia asked me what's the special common feature between the numbers $$1$$, $$\phi$$, $$2$$, $$6$$ and $$10$$. My brain did take about 8 seconds to figure it out, which made me proud. But then I asked the same question to another colleague and it took him about the same time. Can you figure it out too?

The fast answer is a clue. So is the tag.

• Why the downvote??? – Pspl Aug 28 '20 at 11:08
• Wow... That's a little harsh... Well... It's Columbia University in New York, the letter is written "phi" as you can see at wikipedia and I'm Portuguese so I have nothing to do with the White House... – Pspl Aug 28 '20 at 23:12
• @Bass I'm disappointed to see your comment; firstly it doesn't add anything to the question and raises no valid issue with the way the puzzle is constructed. Secondly, Columbia is the U.S. university, your thinking of the country Colombia. – Tonks Sep 1 '20 at 7:12

• I reach the same solution, then I stucked with the 8 secs... only thing that came up in my mind is that $8=2^3$ – Eddymage Aug 28 '20 at 10:25
• If you pay attention to the text, be aware that the number 8 is not even written in LaTeX. That's because it's not a clue itself :) – Pspl Aug 28 '20 at 10:28