Jump to content

Good prime

From Wikipedia, the free encyclopedia

A good prime is a prime number whose square is greater than the product of any two primes at the same number of positions before and after it in the sequence of primes.

That is, good prime satisfies the inequality

for all 1 ≤ in−1, where pk is the kth prime.

Example: the first primes are 2, 3, 5, 7 and 11. Since for 5 both the conditions

are fulfilled, 5 is a good prime.

There are infinitely many good primes.[1] The first good primes are:

5, 11, 17, 29, 37, 41, 53, 59, 67, 71, 97, 101, 127, 149, 179, 191, 223, 227, 251, 257, 269, 307, 311, 331, 347, 419, 431, 541, 557, 563, 569, 587, 593, 599, 641, 727, 733, 739, 809, 821, 853, 929, 937, 967 (sequence A028388 in the OEIS).

An alternative version takes only i = 1 in the definition. With that there are more good primes:

5, 11, 17, 29, 37, 41, 53, 59, 67, 71, 79, 97, 101, 107, 127, 137, 149, 157, 163, 173, 179, 191, 197, 211, 223, 227, 239, 251, 257, 263, 269, 277, 281, 307, 311, 331, 347, 367, 373, 379, 397, 419, 431, 439, 457, 461, 479, 487, 499, 521, 541, 557, 563, 569, 587, 593, 599, 607, 613, 617, 631, 641, 653, 659, 673, 701, 719, 727, 733, 739, 751, 757, 769, 787, 809, 821, 827, 853, 857, 877, 881, 907, 929, 937, 947, 967, 977, 991 (sequence A046869 in the OEIS).

References

[edit]
  1. ^ Weisstein, Eric W. "Good Prime". MathWorld.
pFad - Phonifier reborn

Pfad - The Proxy pFad of © 2024 Garber Painting. All rights reserved.

Note: This service is not intended for secure transactions such as banking, social media, email, or purchasing. Use at your own risk. We assume no liability whatsoever for broken pages.


Alternative Proxies:

Alternative Proxy

pFad Proxy

pFad v3 Proxy

pFad v4 Proxy