Discussion about math, puzzles, games and fun. Useful symbols: ÷ × ½ √ ∞ ≠ ≤ ≥ ≈ ⇒ ± ∈ Δ θ ∴ ∑ ∫ π -¹ ² ³ °

You are not logged in.

- Topics: Active | Unanswered

**anonimnystefy****Real Member**- From: Harlan's World
- Registered: 2011-05-23
- Posts: 16,018

Hm?

Here lies the reader who will never open this book. He is forever dead.

Taking a new step, uttering a new word, is what people fear most. ― Fyodor Dostoyevsky, Crime and Punishment

The knowledge of some things as a function of age is a delta function.

Offline

**cooljackiec****Member**- Registered: 2012-12-13
- Posts: 185

Ok, so that 0.251 thing was correct. and the answer is 30 for the sum of the squares of the digit thing.

I see you have graph paper.

You must be plotting something

Offline

**cooljackiec****Member**- Registered: 2012-12-13
- Posts: 185

The harmonic mean of two positive numbers is the reciprocal of the arithmetic mean of their reciprocals. For how many ordered pairs of positive integers (x, y) with x < y is the harmonic mean equal to 6^{20}?

I see you have graph paper.

You must be plotting something

Offline

**bobbym****Administrator**- From: Bumpkinland
- Registered: 2009-04-12
- Posts: 107,156

Hi cooljackiec;

**In mathematics, you don't understand things. You just get used to them.****If it ain't broke, fix it until it is.**** Always satisfy the Prime Directive of getting the right answer above all else.**

Offline

**cooljackiec****Member**- Registered: 2012-12-13
- Posts: 185

Thanks, this doesn't exactly relate to bases, but:

Find all positive integers n such that

.I see you have graph paper.

You must be plotting something

Offline

**bobbym****Administrator**- From: Bumpkinland
- Registered: 2009-04-12
- Posts: 107,156

Hi cooljackiec;

I have several different definitions of those operators, what is yours?

**In mathematics, you don't understand things. You just get used to them.****If it ain't broke, fix it until it is.**** Always satisfy the Prime Directive of getting the right answer above all else.**

Offline

**cooljackiec****Member**- Registered: 2012-12-13
- Posts: 185

is the number of integers, less than or equal to n, that are relatively prime to n.

is the number of divisors of n

is the number of divisors of n

I see you have graph paper.

You must be plotting something

Offline