## Classic Sequences

**2**

2^n - n^2

**B**

Bell numbers

**C**

Catalan numbers

Central binomial coefficients

Central polygonal numbers

Centred squares

Centred triangular numbers

Collatz function

Cubes

**D**

Digits of e

Digits of pi

**E**

Euler totient

Even numbers

**F**

Factorials

Fibonacci sequence

Fibonacci sequence 1

Formula for primes

Formula for primes 2

**H**

Heptagonal numbers

Hex numbers

Hexagonal numbers

**I**

Integers

**L**

Largest prime divisor

Look and Say sequence

Lucas numbers

**M**

Magic square constants

Mersenne numbers

Mersenne primes

Moebius function

**N**

N nines

N ones

Natural numbers

Number of divisors of central binomial coefficients

Number of letters

**N**

n^n

**O**

Odd numbers

Odd squares

**P**

Partition numbers

Pentagonal numbers

Powers of 2

Primes

Primes with prime subscripts

Primorial

**R**

Regions formed by joining points on a circle

Remove 2s from n

**S**

Sigma

Sigma of n squared

Square pyramid numbers

Squares

Star numbers

Sum of first 3 powers

Sum of first 4 powers

**T**

Tau

Tau of n cubed

Tau of n squared

Tenth powers

Tetrahedral numbers

Triangular numbers

Tribonacci numbers