cp's OEIS Frontend

This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.

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A200503 Record (maximal) gaps between prime sextuplets (p, p+4, p+6, p+10, p+12, p+16).

Original entry on oeis.org

90, 15960, 24360, 1047480, 2605680, 2856000, 3605070, 4438560, 5268900, 17958150, 21955290, 23910600, 37284660, 40198200, 62438460, 64094520, 66134250, 70590030, 77649390, 83360970, 90070470, 93143820, 98228130, 117164040, 131312160, 151078830, 154904820
Offset: 1

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Author

Alexei Kourbatov, Nov 18 2011

Keywords

Comments

Prime sextuplets (p, p+4, p+6, p+10, p+12, p+16) are densest permissible constellations of 6 primes. Average gaps between sextuplets (and, more generally, between prime k-tuples) can be deduced from the Hardy-Littlewood k-tuple conjecture and are O(log^6(p)). Maximal gaps may be significantly larger than average gaps; this sequence suggests that maximal gaps are O(log^7(p)).
A200504 lists initial primes in sextuplets preceding the maximal gaps. A233426 lists the corresponding primes at the end of the maximal gaps.

Examples

			The gap of 15960 between sextuplets with initial primes 97 and 16057 is a maximal gap - larger than any preceding gap; therefore a(2)=15960.
		

Crossrefs

Programs

  • Mathematica
    DeleteDuplicates[Differences[Select[Partition[Prime[Range[10^7]],6,1],Differences[#]=={4,2,4,2,4}&][[;;,1]]],GreaterEqual] (* The program generates the first 10 terms of the sequence. *) (* Harvey P. Dale, May 08 2025 *)

Formula

(1) Conjectured upper bound: gaps between prime sextuplets (p, p+4, p+6, p+10, p+12, p+16) are smaller than 0.058*(log p)^7, where p is the prime at the end of the gap.
(2) Estimate for the actual size of the maximal gap that ends at p: maximal gap = a(log(p/a)-1/3), where a = 0.058*(log p)^6 is the average gap between sextuplets near p, as predicted by the Hardy-Littlewood k-tuple conjecture.
Formulas (1) and (2) are asymptotically equal as p tends to infinity. However, (1) yields values greater than all known gaps, while (2) yields "good guesses" that may be either above or below the actual size of maximal gaps. Both formulas (1) and (2) are derived from the Hardy-Littlewood k-tuple conjecture via probability-based heuristics relating the expected maximal gap size to the average gap. Neither of the formulas has a rigorous proof (the k-tuple conjecture itself has no formal proof either). In both formulas, the constant ~0.058 is reciprocal to the Hardy-Littlewood 6-tuple constant 17.2986...

A233426 Primes p in prime sextuplets (p, p+4, p+6, p+10, p+12, p+16) at the end of the maximal gaps in A200503.

Original entry on oeis.org

97, 16057, 43777, 1091257, 6005887, 14520547, 40660717, 87423097, 94752727, 112710877, 403629757, 1593658597, 2057241997, 5933145847, 6860027887, 14112464617, 23504713147, 24720149677, 29715350377, 29952516817, 45645253597, 53086708387, 58528934197, 93495691687, 97367556817
Offset: 1

Views

Author

Alexei Kourbatov, Dec 09 2013

Keywords

Comments

Prime sextuplets (p, p+4, p+6, p+10, p+12, p+16) are densest permissible constellations of 6 primes. Maximal (record) gaps between prime sextuplets are listed in A200503; see further comments there.

Examples

			Two smallest prime sextuplets (p, p+4, p+6, p+10, p+12, p+16) start at p=7 and p=97; so a[1]=97. The gap of 15960 between sextuplets starting at p=97 and p=16057 is a record gap - larger than any preceding gap; so a[2]=16057. The next gap is not a record, so a new term is not added.
		

Crossrefs

Formula

a(n) = A200504(n) + A200503(n). - Hugo Pfoertner, May 21 2023
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