Recent content by malcolm

:( 9/10 would be much better for me I think

Can't make it if its after the 11th/before the 25th =(

P(x,y)=(2x^2+x+1)^2((2y^2+y+1)^2+1) works. Note that Q(x)=2x^2+x+1 is distinct for each integer x and is strictly positive, so P(x,y) is always a positive integer. Then if P(x,y)=p=a^2b where a,b >0 and b is squarefree, we must have a^2=(2x^2+x+1)^2, b=(2y^2+y+1)^2+1 and since Q(x) is distinct...

Thanks, I've fixed the mistake. The first statement doesn't follow from the second, but the second does tell us that if the sum of three consecutive cubes is always divisible by 9, then we must be able to write \frac{(n-1)^3 + n^3 + (n+1)^3}{9} as a sum of binomial coefficients, since the...

\frac{(n-1)^3 + n^3 + (n+1)^3}{9} = 2C^{n+1}_{3} + n which is obviously an integer. Actually any polynomial in x which takes integer values for integer values of x can be written as a sum of binomial coefficients in x, you can prove this by induction on the degree

I can't do 9-15 or 22, any other day is fine

I'm keen, labour weekend is good

Successful avg 5 - 1:55.37 (1:37.81) 2:44.75 2:14.92 (DNF, 2:13.35, one corner cycle off) = 2:18.35 New memory method is giving much better accuracy

Just been getting back into it, my times are a little slower than what they used to be, though improving quickly. Will there be blindsolving in the competition? I can't see it in the schedule

I'll be there, just registered

My BLD is still only 90sec ish, haven't picked up a cube in ages =/ Ugh I can't come I'm out of the country until the 24th

Hmm I'd like to take a look too

This problem was in a maths competition a participated in, couldn't figure it out. Can anyone enlighten me? All vertices of a 15-gon, not necessarily regular, lie on the circumference of a circle and the centre of this circle is inside the 15-gon. What is the largest possible number of...

Instead of B U' B you can just use f R' f, for less rotations.

I've got sub-20 memo with visual before, and average around 25-40s, but my execution sucks so my PB is 1:28, and I had like a 1:14 DNF. Visual gets much easier with practice, I can memo corners in under 10 secs almost all of the time.