Integer sequence prime

From HandWiki
Short description: Prime number found as a member of an integer sequence


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 (sequence A005042 in the OEIS). Similarly, a constant prime based on Euler's number, 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 [math]\displaystyle{ a_n = n2^n+1 . }[/math]
  • Factorial prime – a prime that appears in either of the sequences [math]\displaystyle{ a_n = n!-1 }[/math] or [math]\displaystyle{ b_n = n!+1 . }[/math]
  • Fermat prime – a prime that appears in the sequence of Fermat numbers [math]\displaystyle{ a_n = 2^{2^n}+1 . }[/math]
  • 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 [math]\displaystyle{ a_n = 2^n-1 . }[/math]
  • Primorial prime – a prime that appears in either of the sequences [math]\displaystyle{ a_n = n\#-1 }[/math] or [math]\displaystyle{ b_n = n\#+1 . }[/math]
  • Pythagorean prime – a prime that appears in the sequence [math]\displaystyle{ a_n = 4n+1 . }[/math]
  • Woodall prime – a prime that appears in the sequence of Woodall numbers [math]\displaystyle{ a_n = n2^n-1 . }[/math]

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.

References