释义 |
Prime ConstellationA prime constellation, also called a Prime k-Tuple or Prime k-Tuplet, is a sequence of consecutivenumbers such that the difference between the first and last is, in some sense, the least possible. More precisely, aprime -tuplet is a sequence of consecutive Primes ( , , ..., ) with , where is the smallest number for which there exist integers , and, for everyPrime , not all the residues modulo are represented by , , ..., (Forbes). For each , thisdefinition excludes a finite number of clusters at the beginning of the prime number sequence. For example, (97, 101,103, 107, 109) satisfies the conditions of the definition of a prime 5-tuplet, but (3, 5, 7, 11, 13) does not becauseall three residues modulo 3 are represented (Forbes).
A prime double with is of the form ( , ) and is called a pair of Twin Primes. Prime doubles of the form( , ) are called Sexy Primes. A prime triplet has . The constellation ( , , ) cannot exist,except for , since one of , , and must be divisible by three. However, there are several types of primetriplets which can exist: ( , , ), ( , , ), ( , , ). A Prime Quadruplet is aconstellation of four successive Primes with minimal distance , and is of the form ( , , , ). The sequence therefore begins 2, 6, 8, and continues 12, 16, 20, 26, 30, ... (Sloane's A008407). Another quadrupletconstellation is ( , , , ).
The first First Hardy-Littlewood Conjecture states that the numbers ofconstellations are asymptotically given by These numbers are sometimes called the Hardy-Littlewood Constants. (1) is sometimes called the extended TwinPrime Conjecture, and
 | (8) |
where is the Twin Primes Constant. Riesel (1994) remarks that the Hardy-Littlewood Constants can becomputed to arbitrary accuracy without needing the infinite sequence of primes.
The integrals above have the analytic forms
where is the Logarithmic Integral.
The following table gives the number of prime constellations , and the second table gives the valuespredicted by the Hardy-Littlewood formulas. Count |  |  |  |  |  | 1224 | 8169 | 58980 | 440312 |  | 1216 | 8144 | 58622 | 440258 |  | 2447 | 16386 | 117207 | 879908 |  | 259 | 1393 | 8543 | 55600 |  | 248 | 1444 | 8677 | 55556 |  | 38 | 166 | 899 | 4768 |  | 75 | 325 | 1695 | 9330 |
Hardy-Littlewood |  |  |  |  |  | 1249 | 8248 | 58754 | 440368 |  | 1249 | 8248 | 58754 | 440368 |  | 2497 | 16496 | 117508 | 880736 |  | 279 | 1446 | 8591 | 55491 |  | 279 | 1446 | 8591 | 55491 |  | 53 | 184 | 863 | 4735 |  | | | | |
Consider prime constellations in which each term is of the form . Hardy and Littlewood showed that the numberof prime constellations of this form is given by
 | (12) |
where
 | (13) |
(Le Lionnais 1983).
Forbes gives a list of the ``top ten'' prime -tuples for . The largest known 14-constellations are( , 2, 8, 14, 18, 20, 24, 30, 32, 38, 42, 44, 48, 50),( , 2, 8, 14, 18, 20, 24, 30, 32, 38, 42, 44, 48, 50),( , 2, 8, 14, 18, 20, 24, 30, 32, 38, 42, 44, 48, 50),( , 2, 8, 14, 18, 20, 24, 30, 32, 38, 42, 44, 48, 50),( , 2, 6, 8, 12, 18, 20, 26, 30, 32, 36, 42, 48, 50).
The largest known prime 15-constellations are( , 2, 6, 12, 14, 20, 24, 26, 30, 36, 42, 44, 50, 54, 56),( , 2, 6, 12, 14, 20, 26, 30, 32, 36, 42, 44, 50, 54, 56),( , 2, 6, 12, 14, 20, 26, 30, 32, 36, 42, 44, 50, 54, 56),( , 2, 6, 12, 14, 20, 26, 30, 32, 36, 42, 44, 50, 54, 56),( , 2, 6, 12, 14, 20, 24, 26, 30, 36, 42, 44, 50, 54, 56).
The largest known prime 16-constellations are( , 2, 6, 12, 14, 20, 26, 30, 32, 36, 42, 44, 50, 54, 56, 60),( , 2, 6, 12, 14, 20, 26, 30, 32, 36, 42, 44, 50, 54, 56, 60),( , 2, 6, 12, 14, 20, 26, 30, 32, 36, 42, 44, 50, 54, 56, 60), (13, 17, 19, 23, 29, 31, 37, 41, 43, 47, 53, 59, 61, 67, 71, 73).
The largest known prime 17-constellations are ( , 6, 8, 12, 18, 20, 26, 32, 36, 38, 42, 48, 50, 56, 60, 62, 66),(17, 19, 23, 29, 31, 37, 41, 43, 47, 53, 59, 61, 67, 71, 73, 79, 83)(13, 17, 19, 23, 29, 31, 37, 41, 43, 47, 53, 59, 61, 67, 71, 73, 79). See also Composite Runs, Prime Arithmetic Progression, k-Tuple Conjecture,Prime k-Tuples Conjecture, Prime Quadruplet, Sexy Primes,Twin Primes References
Forbes, T. ``Prime -tuplets.'' http://www.ltkz.demon.co.uk/ktuplets.htm. Guy, R. K. ``Patterns of Primes.'' §A9 in Unsolved Problems in Number Theory, 2nd ed. New York: Springer-Verlag, pp. 23-25, 1994. Le Lionnais, F. Les nombres remarquables. Paris: Hermann, p. 38, 1983. Riesel, H. Prime Numbers and Computer Methods for Factorization, 2nd ed. Boston, MA: Birkhäuser, pp. 60-74, 1994. Sloane, N. J. A. Sequence A008407in ``The On-Line Version of the Encyclopedia of Integer Sequences.''http://www.research.att.com/~njas/sequences/eisonline.html.
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