# What are the famous sequences?

Table of Contents

## What are the famous sequences?

Some Famous Sequences

- Recamán’s sequence, A005132.
- The Busy Beaver problem, A060843.
- The Catalan numbers, A000108.
- The prime numbers, A000040.
- The Mersenne primes, A000043 and A000668.
- The Fibonacci numbers, A000045.

**How many sequences are in the Oeis?**

341,962 sequences

OEIS records information on integer sequences of interest to both professional and amateur mathematicians, and is widely cited. As of March 2021 it contains 341,962 sequences, making it the largest database of its kind.

### What is A000040?

Description. Under OEIS A000040, a Prime number is a natural number with no positive divisors other than 1 and itself.

**How do you use Oeis?**

Hints for Using On-Line Encyclopedia of Integer Sequences (or OEIS)

- Enter about 6 terms, starting with the second term. Leave off the first term or two, because people may disagree about where the sequence begins.
- Clean up your sequence first.

## What is interesting sequence?

(1) Fibonacci Series: Probably the most famous of all Mathematical sequences; it goes like this—- 1,1,2,3,5,8,13,21,34,55,89… At first glance one may wonder what makes this sequence of numbers so sacrosanct or important or famous.

**Which sequence is most important?**

### What are the types of sequences in math?

There are mainly four types of sequences in Arithmetic, Arithmetic Sequence, Geometric Sequence, Harmonic Sequence, and Fibonacci Sequence.

**What’s the weirdest number in the world?**

The smallest weird number is 70. Its proper divisors are 1, 2, 5, 7, 10, 14, and 35; these sum to 74, but no subset of these sums to 70.

## Is 49 a happy number?

The first few happy numbers are 1, 7, 10, 13, 19, 23, 28, 31, 32, 44, 49, 68, 70, 79, 82, 86, 91, 94, 97, 100. (OEIS A007770).

**What is not a prime number?**

Definition: A prime number is a whole number with exactly two integral divisors, 1 and itself. The number 1 is not a prime, since it has only one divisor. The number 4 is not prime, since it has three divisors ( 1 , 2 , and 4 ), and 6 is not prime, since it has four divisors ( 1 , 2 , 3 , and 6 ).

### What does offset mean in Oeis?

The offset in an OEIS sequence entry gives the index of the first term of the sequence (in other words, it tells us where the sequence starts).

**What are some of the most interesting OEIS sequences?**

Recamán’s sequence, A005132 The Busy Beaver problem, A060843 The Catalan numbers, A000108 The prime numbers, A000040 The Mersenne primes, A000043and A000668 The Fibonacci numbers, A000045 For some other fascinating sequences see Pictures from the OEIS: The (Free) OEIS Store General Information About OEIS

## What are some examples of famous sequences?

Some Famous Sequences Click on any of the following to see examples of famous sequences in the On-Line Encyclopedia of Integer Sequences(the OEIS), then hit “Back” in your browser to return here: Recamán’s sequence, A005132 The Busy Beaver problem, A060843 The Catalan numbers, A000108 The prime numbers, A000040

**How can I find out if a number sequence has been studied?**

If you come across a number sequence and want to know if it has been studied before, there is only one place to look, the On-Line Encyclopedia of Integer Sequences (or OEIS). Now in its 49th year, the OEIS contains over 220,000 sequences and 20,000 new entries are added each year.

### What if my favorite sequence isn’t in the database?

If your favorite sequence isn’t in the database, and if it is interesting, please submit it using the web page for Contributing a new sequence or comment. Of course the sequence should be well-defined, of general interest and ideally it should be infinite. Short sequences such as phone numbers are not appropriate.