Note from OEIS Editor: This is a cached copy of Dennis R. Martin's "Elite Prime Search", obtained from Internet Archive with URL http://web.archive.org/web/20131208103921/http://primenace.com/papers/math/ElitePrimes.htm, and stored with permission of the author at OEIS. The name of this document should stay as a102742.html so that the links from other two cached documents will work as expected.

Elite Prime Search

Complete to 1E14

Dennis R. Martin

DP Technology Corp., Camarillo, CA

dennis.martin@dptechnology.com

There are 29 elite primes less than 5E12 but no more between 5E12 and 1E14. As of February 4, 2009, this search is complete up to 1E14.

A prime number p is elite if only finitely many Fermat numbers Fm = 2^(2m) + 1 are quadratic residues of p, while p is anti-elite if only finitely many Fermat numbers are quadratic non-residues of p. Both elite and anti-elite primes were searched for simultaneously in this study using a method based on articles by Chaumont and Müller [1] and Müller [2]. A detailed description is given under Elite and Anti-Elite Search Methodology.

In the table below the Exponent m is the smallest nonnegative integer such that Fm = 2^(2m)+1 rs (mod p), where s represents the start of the of the Fermat period (s S, with S being the latest possible Fermat period start derived from Aigner [4]). The length of the Fermat period L is the smallest positive integer such that Fm+L Fm rs (mod p), and the Jacobi Symbol (rk | Fn) applies to all n m and to all k s (specifically in the interval from s to s + L – 1, after which the residues repeat). Hence the prime p can only be a quadratic residue, with (rk | Fn) = 1, for a finite number of Fermat numbers, at most those with n < m.

 # Anti-Elite Prime, p First Repeating Residue, rs Exponent m Fermat Period L Jacobi Symbol (rk | Fn) p mod 240 1 3 2 1 1 -1 3 2 5 2 2 1 -1 5 3 7 3 0 2 -1 7 4 41 17 2 4 -1 41 5 15361 8937 8 4 -1 1 6 23041 9692 5 4 -1 1 7 26881 2767 6 4 -1 1 8 61441 60426 10 4 -1 1 9 87041 41476 9 8 -1 161 10 163841 74103 14 4 -1 161 11 544001 221652 7 8 -1 161 12 604801 360626 6 6 -1 1 13 6684673 3689982 16 8 -1 193 14 14172161 9839337 13 4 -1 161 15 159318017 127581454 13 8 -1 17 16 446960641 264969553 7 4 -1 1 17 1151139841 861720124 12 4 -1 1 18 3208642561 1375589497 20 4 -1 1 19 38126223361 9882944985 22 4 -1 1 20 108905103361 39278554590 21 4 -1 1 21 171727482881 161773654636 8 8 -1 161 22 318093312001 287792761689 13 4 -1 1 23 443069456129 84762800455 6 8 -1 209 24 912680550401 361573893908 30 4 -1 161 25 1295536619521 1144718793846 25 4 -1 1 26 1825696645121 980255578452 25 4 -1 161 27 2061584302081 967053839472 35 4 -1 1 28 2769999339521 1001509752664 12 4 -1 161 29 3580135407617 123155921421 15 8 -1 17

Note that the first two Fermat primes, F0 = 3 and F1 = 5, are elite, while all other Fermat primes as well as all prime divisors of composite Fermat numbers must be anti-elite. Prime divisors of Fermat numbers are compiled by Keller [5].

The elite and anti-elite primes appear as sequences A102742 and A128852 in Sloane’s Online Encyclopedia of Integer Sequences (OEIS) [6].

The sum of the reciprocals of the first 29 elite primes is 0.7007640115758556998739637117…. This sum has been proven to be convergent by Kķ˛ek, Luca, and Somer [7].

The last column in the table gives the residue of p mod 240. These residue classes are used as part of the Elite and Anti-Elite Search Methodology. It is interesting to note that thirteen of the first 29 elite primes have a residue of 1 (mod 240), and therefore a residue of 1 (mod 120), while eight others have a residue of 161 (mod 240), which when combined with 41 gives nine elite primes that have a residue of 41 (mod 120). Since no p > 5  can have a residue of 3 or 5 (mod 30), only four other possible residues are represented in this column, with 17 being the only other residue modulo 240 that is repeated out of the first 29. Out of (240) = 64 residue classes 26 cannot be elite, leaving 38 possible elite residues modulo 240. But of those 38 only 7 have appeared so far.

For a list of anti-elite primes, see the corresponding Anti-Elite Prime Search page [8].

References

[1] Alain Chaumont and Tom Mueller, All Elite Primes Up to 250 Billion,

J. Integer Sequences, Vol. 9 (2006), Article 06.3.8.

[2] Tom Mueller, On Anti-Elite Prime Numbers,

J. Integer Sequences, Vol. 10 (2007), Article 07.9.4.

[3] Chris Caldwell, The Prime Pages: Jacobi symbol.

[4] Alexander Aigner; Üeber Primzahlen, nach denen (fast) alle Fermatzahlen

quadratische Nichtreste sind. Monatsh. Math. 101 (1986), pp. 85-93.

[5] Wilfrid Keller, Fermat factoring status.

[6] N. J. A. Sloane, Online Encyclopedia of Integer Sequences (OEIS), electronically published at: https://oeis.org/.

[7] M. Kķ˛ek, F. Luca, L. Somer, On the convergence of series of reciprocals of primes related to the Fermat numbers. J. Number Theory 97 (2002), 95–112.

[8] Dennis R. Martin, Anti-Elite Prime Search.