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A192870 The maximum integer M such that there are no prime n-tuplets of any possible pattern between M^2 and (M+1)^2, or -1 if no such maximum M exists. 2
0, 122, 3113, 719377, 15467683 (list; graph; refs; listen; history; text; internal format)



All terms are conjectural. A prime n-tuplet is defined as the densest permissible prime constellation containing n primes. The term a(2) corresponds to twin primes, a(3) to prime triplets, a(4) to prime quadruplets, etc. Extensive computational evidence suggests that these terms are valid. However, there is no proof that the greatest integer M exists - not even for a subset of values of n. If one could find a constructive existence proof, then Twin Prime Conjecture as well as Legendre's Conjecture would require just a trivial additional step. - Edited by Hugo Pfoertner, Sep 15 2021

Note that, for some n, a prime (n+1)-tuple must include a prime n-tuple; e.g., prime quadruplets include prime triples. Thus, if any term is -1,  subsequent terms may be -1, too. - Franklin T. Adams-Watters and Alexei Kourbatov, Jul 14 2011

However, for other n, a prime (n+1)-tuple does NOT include a prime n-tuple; e.g. 7-tuples {p, p + 2, p + 6, p + 8, p + 12, p + 18, p + 20} do not contain 6-tuples {p-4, p, p + 2, p + 6, p + 8, p + 12}; see List of all possible patterns of prime k-tuplets by Tony Forbes.

Assuming the Hardy-Littlewood k-tuple conjecture, the average distance between k-tuples grows slower than the distance between consecutive squares. This is an indication (but not a proof) that the maximum integer M in A192870 does exist for all n.


Table of n, a(n) for n=1..5.

Tony Forbes and Norman Luhn, List of all possible patterns of prime k-tuplets (up to k=50)

A. Kourbatov, Maximal gaps between prime k-tuples: a statistical approach, arXiv preprint arXiv:1301.2242, 2013 and J. Int. Seq. 16 (2013) #13.5.2

G. H. Hardy and J. E. Littlewood, Some problems of 'Partitio numerorum'; III: on the expression of a number as a sum of primes, Acta Mathematica, Vol. 44, pp. 1-70, 1923.

Eric W. Weisstein, k-Tuple Conjecture


The term a(4)=719377 means that there are no prime quadruplets between 719377^2 and 719378^2, but there are prime quadruplets between m^2 and (m+1)^2 for m > 719377.


Cf. A091592: Numbers n such that there are no twin primes between n^2 and (n+1)^2; A008407: Minimal width of prime n-tuplet. Cf. A020497.

Sequence in context: A208049 A276252 A259528 * A208432 A275356 A275146

Adjacent sequences:  A192867 A192868 A192869 * A192871 A192872 A192873




Alexei Kourbatov, Jul 11 2011


First term, 0, added and offset changed by Zak Seidov, Jul 11 2011

Clarification regarding patterns in the title added by Hugo Pfoertner, Sep 15 2021



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Last modified September 21 04:10 EDT 2021. Contains 347596 sequences. (Running on oeis4.)