Integer sequence prime

Integer sequence prime

In mathematics, an integer sequence prime is a prime number found as a member of an integer sequence. For example, the 8th Delannoy number, 265729, is prime. A challenge in empirical mathematics is to identify large prime values in rapidly-growing sequences.

A common subclass of integer sequence primes are constant primes, formed by taking a constant real number and considering prefixes of its decimal representation, omitting the decimal point. For example, the first 6 decimal digits of the constant π, approximately 3.14159265, form the prime number 314159, which is therefore known as a pi-prime. Similarly, a constant prime based on e is called an e-prime.

Other examples of integer sequence primes include:

  • Cullen prime – a prime that appears in the sequence of Cullen numbers a_n=n2^n+1\, .
  • Factorial prime – a prime that appears in either of the sequences an = n! − 1 or b_n=n!+1\, .
  • Fermat prime – a prime that appears in the sequence of Fermat numbers a_n=2^{2^n}+1\, .
  • Fibonacci prime – a prime that appears in the sequence of Fibonacci numbers.
  • Lucas prime – a prime that appears in the Lucas numbers.
  • Mersenne prime – a prime that appears in the sequence of Mersenne numbers a_n=2^n-1\, .
  • Primorial prime – a prime that appears in either of the sequences a_n=n\#-1 or b_n=n\#+1\, .
  • Pythagorean prime – a prime that appears in the sequence a_n=4n+1\, .
  • Woodall prime – a prime that appears in the sequence of Woodall numbers a_n=n2^n-1\, .

The On-Line Encyclopedia of Integer Sequences includes many sequences corresponding to the prime subsequences of well-known sequences, for example A001605 for Fibonacci numbers that are prime.

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