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