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Super-prime

From Wikipedia, the free encyclopedia

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

3, 5, 11, 17, 31, 547, 739, 877, 1087, 1153, 2081, 2381,... (sequenceA124173in theOEIS).

References

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  • 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).
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