Super-prime
Super-prime numbers,also known ashigher-order primesorprime-indexed primes(PIPs), are thesubsequenceofprime numbersthat occupy prime-numbered positions within the sequence of all prime numbers. In other words, if prime numbers are matched with ordinal numbers, starting with prime number 2 matched with ordinal number 1, the primes matched with prime ordinal numbers are the super primes.
The subsequence begins
- 3, 5, 11, 17, 31, 41, 59, 67, 83, 109, 127, 157, 179, 191, 211, 241, 277, 283, 331, 353, 367, 401, 431, 461, 509, 547, 563, 587, 599, 617, 709, 739, 773, 797, 859, 877, 919, 967, 991,... (sequenceA006450in theOEIS).
That is, ifp(n) denotes thenth prime number, the numbers in this sequence are those of the formp(p(n)).
n | 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 | 10 | 11 | 12 | 13 | 14 | 15 | 16 | 17 | 18 | 19 | 20 |
---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
p(n) | 2 | 3 | 5 | 7 | 11 | 13 | 17 | 19 | 23 | 29 | 31 | 37 | 41 | 43 | 47 | 53 | 59 | 61 | 67 | 71 |
p(p(n)) | 3 | 5 | 11 | 17 | 31 | 41 | 59 | 67 | 83 | 109 | 127 | 157 | 179 | 191 | 211 | 241 | 277 | 283 | 331 | 353 |
Dressler & Parker (1975)used a computer-aided proof (based on calculations involving thesubset sum problem) to show that every integer greater than 96 may be represented as a sum of distinct super-prime numbers. Their proof relies on a result resemblingBertrand's postulate,stating that (after the larger gap between super-primes 5 and 11) each super-prime number is less than twice its predecessor in the sequence.
Broughan & Barnett (2009)show that there are
super-primes up tox. This can be used to show that the set of all super-primes issmall.
One can also define "higher-order" primeness much the same way and obtain analogous sequences of primes (Fernandez 1999).
A variation on this theme is the sequence of prime numbers withpalindromic primeindices, beginning with
References
[edit]- Bayless, Jonathan; Klyve, Dominic; Oliveira e Silva, Tomás (2013),"New bounds and computations on prime-indexed primes",Integers,13:A43:1–A43:21,MR3097157
- Broughan, Kevin A.; Barnett, A. Ross (2009),"On the subsequence of primes having prime subscripts",Journal of Integer Sequences,12,article 09.2.3.
- Dressler, Robert E.; Parker, S. Thomas (1975), "Primes with a prime subscript",Journal of the ACM,22(3): 380–381,doi:10.1145/321892.321900,MR0376599.
- Fernandez, Neil (1999),An order of primeness, F(p).