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A046789

Lower prime of the second gap of 2n between primes.

5, 13, 31, 359, 181, 211, 293, 1933, 1069, 1637, 1951, 2179, 3137, 3271, 4831, 10799, 8467, 12853, 38393, 20809, 34981, 36389, 91033, 73189, 45893, 25471, 40289, 153191, 58831, 102701, 190409, 107377, 221327, 290249, 175141, 360091

(list; graph; refs; listen; history; text; internal format)

OFFSET

1,1

REFERENCES

Enoch Haga, Exploring Prime Numbers on Your PC, 2nd edition, 1998, ISBN 1-885794-16-9, Table 4, pages 38-39.

LINKS

Robert G. Wilson v, Table of n, a(n) for n = 1..257

FORMULA

a(n) = A000230(n) + A046728(n). - Robert G. Wilson v, Nov 26 2020

EXAMPLE

The second prime gap of 4 is at 13 to 17, so a(2)=13.

MATHEMATICA

Flatten[Table[First /@ Take[Select[Partition[Prime[Range[32000]], 2, 1], Differences[#] == {2 n} &], {2}], {n, 36}]] (* Jayanta Basu, Jun 28 2013 *)

tt[_] := -2; p0 = NextPrime@2; p1 = NextPrime@p0; While[p0 < 25000000, diff = (p1 - p0)/2; If[tt[diff] == -1, tt[diff] = p0]; If[tt[diff] == -2, tt[diff] = -1]; {p0, p1} = {p1, NextPrime@p1}]; tt@# & /@ Range@77 (* Robert G. Wilson v, Nov 26 2020 *)

CROSSREFS

Cf. A000230, A046728.

Sequence in context: A146057 A062403 A066688 * A271902 A272539 A066184

Adjacent sequences: A046786 A046787 A046788 * A046790 A046791 A046792

KEYWORD

nonn

AUTHOR

Jud McCranie

STATUS

approved

URL: https://oeis.org/A046789

⇱ A046789 - OEIS