Putnam Exam

How'd Veeky Forums do on your Putnam exam today?
Which questions did you attempt?

Did you remember to properly fold your icosidodecahedron?

>being an undergrad

I did A-1 and B-2

Neat! How do you feel about it?
I think most people would've been able to compose rules (c) and (b) to show that 2+5n where n>=1 exists in S. One kid did something fancy with modulo math and was able to pull in a bunch of other stuff too.

Posting problem A-1

Someone bully my answer for A-6.
I'm a [spoiler]finance major[/spoiler], so I don't know a lot of the symbols but I'd like to see the right way if someone knows.

Yeah and then you can find expressions for 3,4,6 to be in S. Pretty easy once you know the trick

I did A2 A3 B1 and B2 but I got B2 wrong

Had an idea but couldn't explain B6

I'm pretty sure that's a really tiny fraction of the possible sequences.

the question

What'd you get for it?

I eventually gave up but it should be around 2017^63 because for any x1,x2...x63 there should be an x0 that would make it a multiple of 2017 and it usually won't be one of the other xn.

What'd you get for A2, im guessing if you tried B6 then you did A2

Was A2 the integral one? Also I did A2 first because you have to do the A section then the B section.

It's the q(x) question, it took doing many discrete examples before seeing a pattern for me lol

Oh okay I proved An=qn-1*x-qn-2 by induction

That's what I did, and it relied on rewriting the numerator

Neat I wondered if that was a common solution for me I kinda just stumbled into it.
Nice

For the integral from a to b one I had a 2 page slog of epsilon Delta arguments. was there a trick?

Sorry wrong reply I'm not used to the app I'm using.

Math is fucking gay you nerds

I did A-1 and A-3? I got a migraine during the second part and left.

No you're gay!

I did A-1 and B-1 and only got partial results on A-2 and B-2. I figured out how to do them but didn't have enough time to properly write out the solution, especially for B-2, B-1 was a massive time sink for me.

did you put 1009?
lol

Did A-1, B-1, and B-2. First time so I was pretty happy about that.
I worked for a while on A-2 and A-3 but didn't really get anywhere. No idea how to show integer coefs for A-2, and I haven't taken proper analysis.
I wanted to try B-6 really bad, but I figured it was tougher than I was giving it credit so I didn't try.
Also, I have no idea how to do B-3 or B-4. Any ideas?