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Here are programs for some popular sequences. Links to the complete program lists can be found at the bottom of this page. There are currently more than 100,000 programs for integer sequences available.
Deprecated. Please use the interactive programs browser
- A000005 (program): Number of divisors of n:
tau(n) - A000010 (program): Euler totient function:
phi(n) - A000040 (program): Prime numbers
- A000203 (program): Sum of divisors of n:
sigma(n) - A000720 (program): Number of primes <= n:
pi(n) - A001031 (program): Goldbach conjecture: number of decompositions of 2n into sum of two primes (counting 1 as a prime)
- A001221 (program): Number of prime divisors of n:
omega(n) - A008683 (program): Möbius function:
mu(n)
- A000796 (program): Decimal expansion of
pi - A001113 (program): Decimal expansion of
e - A001622 (program): Decimal expansion of golden ratio
- A002117 (program): Decimal expansion of
zeta(3) - A002163 (program): Decimal expansion of square root of 5
- A000008 (program): Number of ways of making change for n cents using coins of 1, 2, 5, 10 cents
- A000041 (program): Partition numbers
- A000108 (program): Catalan numbers
- A000110 (program): Bell or exponential numbers
- A000118 (program): Number of ways of writing n as a sum of 4 squares
- A000387 (program): Rencontres numbers
- A000045 (program): Fibonacci numbers
- A000142 (program): Factorial numbers
- A000932 (program):
a(n) = a(n-1) + n*a(n-2), a(0) = a(1) = 1 - A001042 (program):
a(n) = a(n-1)^2 - a(n-2)^2, a(0) = 1, a(1) = 2 - A002487 (program): Stern's diatomic series:
a(2*n) = a(n), a(2*n+1) = a(n) + a(n+1), a(0) = 0, a(1) = 1
- A010051 (program): Characteristic function of primes
- A010052 (program): Characteristic function of squares
- A010058 (program): Characteristic function of Catalan numbers
- A012245 (program): Characteristic function of factorial numbers
- A066247 (program): Characteristic function of composite numbers
- A000120 (program): 1's-counting sequence
- A003132 (program): Sum of squares of digits of n
- A004086 (program): Read n backwards
- A004186 (program): Arrange digits of n in decreasing order
- A007088 (program): The binary numbers: numbers written in base 2
- A003188 (program): Decimal equivalent of Gray code for n
- A003415 (program): Arithmetic derivative of n:
a(prime) = 1, a(m*n) = m*a(n) + n*a(m), a(0) = a(1) = 0 - A007318 (program): Pascal's triangle read by rows
- A006577 (program): Number of halving and tripling steps to reach 1 in '3x+1' problem
- A007435 (program): Inverse Möbius transform of Fibonacci numbers