Prime powers

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Prime powers are prime numbers raised to powers. For example, 729 is a prime power, being 3 6. Technically, the primes themselves are prime powers, too, with exponent 1, but generally an exponent of 2 or greater is meant. (Along similar lines, the number 1 is technically a prime power as well, with the exponent being 0.)

Representation of n based on its factorization into maximal prime powers

See Representation of n based on its factorization into maximal prime powers.

Representation of n based on its factorization into prime powers with powers of two as exponents

See Representation of n based on its factorization into prime powers with powers of two as exponents, Ordering of positive integers by increasing representation based on their factorization into prime powers with powers of two as exponents.

Number of factorizations of n into prime powers greater than 1

The number of factorizations of n into prime powers greater than 1 is given by (A000688)

$a(n)=\prod _{i=1}^{\omega (n)}p(\alpha _{i}),\,$

where $\scriptstyle \omega (n)\,$ is the number of distinct prime factors of $\scriptstyle n\,$, $\scriptstyle p(n)\,$ is the number of partitions of $\scriptstyle n\,$ and the $\scriptstyle \alpha _{i}\,$ are the exponents of the distinct prime factors $\scriptstyle p_{i}\,$ of $\scriptstyle n\,$

$n=\prod _{i=1}^{\omega (n)}p_{i}^{\alpha _{i}}\,$

Sequences

Sequences for p^k (p prime, k >= 0)

Prime powers p^k (p prime, k >= 0). (A000961)

{1, 2, 3, 4, 5, 7, 8, 9, 11, 13, 16, 17, 19, 23, 25, 27, 29, 31, 32, 37, 41, 43, 47, 49, 53, 59, 61, 64, 67, 71, 73, 79, 81, 83, 89, 97, 101, 103, 107, 109, 113, 121, 125, 127, 128, 131, 137, 139, 149, 151, ...}

a(1) = 1; for n > 1, a(n) = prime root of n-th prime power (A025473)

{1, 2, 3, 2, 5, 7, 2, 3, 11, 13, 2, 17, 19, 23, 5, 3, 29, 31, 2, 37, 41, 43, 47, 7, 53, 59, 61, 2, 67, 71, 73, 79, 3, 83, 89, 97, 101, 103, 107, 109, 113, 11, 5, 127, 2, 131, 137, 139, 149, 151, 157, 163, 167, 13, ...}

Exponent of n-th prime power (A000961). (A025474)

{0, 1, 1, 2, 1, 1, 3, 2, 1, 1, 4, 1, 1, 1, 2, 3, 1, 1, 5, 1, 1, 1, 1, 2, 1, 1, 1, 6, 1, 1, 1, 1, 4, 1, 1, 1, 1, 1, 1, 1, 1, 2, 3, 1, 7, 1, 1, 1, 1, 1, 1, 1, 1, 2, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 5, 1, 8, 1, 1, 1, 1, ...}

If n = k-th prime power then k else 0, n >= 1. (A095874)

{1, 2, 3, 4, 5, 0, 6, 7, 8, 0, 9, 0, 10, 0, 0, 11, 12, 0, 13, 0, 0, 0, 14, 0, 15, 0, 16, 0, 17, 0, 18, 19, 0, 0, 0, 0, 20, 0, 0, 0, 21, 0, 22, 0, 0, 0, 23, 0, 24, 0, 0, 0, 25, 0, 0, 0, 0, 0, 26, 0, 27, 0, 0, 28, 0, 0, 29, ...}

1 if n, n >= 1, is a prime power p^k (k >= 0), otherwise 0. (A010055)

{1, 1, 1, 1, 1, 0, 1, 1, 1, 0, 1, 0, 1, 0, 0, 1, 1, 0, 1, 0, 0, 0, 1, 0, 1, 0, 1, 0, 1, 0, 1, 1, 0, 0, 0, 0, 1, 0, 0, 0, 1, 0, 1, 0, 0, 0, 1, 0, 1, 0, 0, 0, 1, 0, 0, 0, 0, 0, 1, 0, 1, 0, 0, 1, 0, 0, 1, 0, 0, 0, 1, 0, 1, 0, ...}

Number of prime powers <= n, n >= 1. (A065515)

{1, 2, 3, 4, 5, 5, 6, 7, 8, 8, 9, 9, 10, 10, 10, 11, 12, 12, 13, 13, 13, 13, 14, 14, 15, 15, 16, 16, 17, 17, 18, 19, 19, 19, 19, 19, 20, 20, 20, 20, 21, 21, 22, 22, 22, 22, 23, 23, 24, 24, 24, 24, 25, 25, 25, ...}

Sequences for p^k (p prime, k >= 1)

If n, n >= 1, is a prime power p^k, k >= 1, then n, otherwise 1. (A100994)

{1, 2, 3, 4, 5, 1, 7, 8, 9, 1, 11, 1, 13, 1, 1, 16, 17, 1, 19, 1, 1, 1, 23, 1, 25, 1, 27, 1, 29, 1, 31, 32, 1, 1, 1, 1, 37, 1, 1, 1, 41, 1, 43, 1, 1, 1, 47, 1, 49, 1, 1, 1, 53, 1, 1, 1, 1, 1, 59, 1, 61, 1, 1, 64, 1, 1, 67, ...}

a(n) = 1 unless n, n >= 1, is a prime or prime power when a(n) = the prime in question (exponential of Mangoldt function M(n), which is log(p) if n=p^k otherwise 0). (A014963)

{1, 2, 3, 2, 5, 1, 7, 2, 3, 1, 11, 1, 13, 1, 1, 2, 17, 1, 19, 1, 1, 1, 23, 1, 5, 1, 3, 1, 29, 1, 31, 2, 1, 1, 1, 1, 37, 1, 1, 1, 41, 1, 43, 1, 1, 1, 47, 1, 7, 1, 1, 1, 53, 1, 1, 1, 1, 1, 59, 1, 61, 1, 1, 2, 1, 1, 67, ...}

If n, n >= 1, is a prime power p^k, k >= 1, then k, otherwise 0. (A100995)

{0, 1, 1, 2, 1, 0, 1, 3, 2, 0, 1, 0, 1, 0, 0, 4, 1, 0, 1, 0, 0, 0, 1, 0, 2, 0, 3, 0, 1, 0, 1, 5, 0, 0, 0, 0, 1, 0, 0, 0, 1, 0, 1, 0, 0, 0, 1, 0, 2, 0, 0, 0, 1, 0, 0, 0, 0, 0, 1, 0, 1, 0, 0, 6, 0, 0, 1, 0, 0, 0, 1, 0, 1, 0, 0, 0, 0, ...}

Number of factorizations of n into prime powers greater than 1; number of Abelian groups of order n. (A000688)

{1, 1, 1, 2, 1, 1, 1, 3, 2, 1, 1, 2, 1, 1, 1, 5, 1, 2, 1, 2, 1, 1, 1, 3, 2, 1, 3, 2, 1, 1, 1, 7, 1, 1, 1, 4, 1, 1, 1, 3, 1, 1, 1, 2, 2, 1, 1, 5, 2, 2, 1, 2, 1, 3, 1, 3, 1, 1, 1, 2, 1, 1, 2, 11, 1, 1, 1, 2, 1, 1, 1, 6, 1, 1, 2, 2, ...}

Number of prime powers <= n, n >= 1, with exponents > 0. (A025528)

{0, 1, 2, 3, 4, 4, 5, 6, 7, 7, 8, 8, 9, 9, 9, 10, 11, 11, 12, 12, 12, 12, 13, 13, 14, 14, 15, 15, 16, 16, 17, 18, 18, 18, 18, 18, 19, 19, 19, 19, 20, 20, 21, 21, 21, 21, 22, 22, 23, 23, 23, 23, 24, 24, 24, 24, ...}

Sequences for p^k (p prime, k = 0 or k >= 2)

Prime powers p^k, k = 0 or k >= 2, thus excluding the primes, n >= 1. (A025475)

{1, 4, 8, 9, 16, 25, 27, 32, 49, 64, 81, 121, 125, 128, 169, 243, 256, 289, 343, 361, 512, 529, 625, 729, 841, 961, 1024, 1331, 1369, 1681, 1849, 2048, 2187, 2197, 2209, 2401, 2809, 3125, 3481, ...}

See also

• Prime numbers
• Perfect powers
• Kronecker decomposition theorem
• Representation of n based on its factorization into maximal prime powers.
• Representation of n based on its factorization into prime powers with powers of two as exponents.