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%I #41 Oct 14 2022 04:15:35
%S 5,13,31,359,181,211,293,1933,1069,1637,1951,2179,3137,3271,4831,
%T 10799,8467,12853,38393,20809,34981,36389,91033,73189,45893,25471,
%U 40289,153191,58831,102701,190409,107377,221327,290249,175141,360091
%N Lower prime of the second gap of 2n between primes.
%D Enoch Haga, Exploring Prime Numbers on Your PC, 2nd edition, 1998, ISBN 1-885794-16-9, Table 4, pages 38-39.
%H Robert G. Wilson v, <a href="/A046789/b046789.txt">Table of n, a(n) for n = 1..257</a>
%F a(n) = A000230(n) + A046728(n). - _Robert G. Wilson v_, Nov 26 2020
%e The second prime gap of 4 is at 13 to 17, so a(2)=13.
%t Flatten[Table[First /@ Take[Select[Partition[Prime[Range[32000]], 2, 1], Differences[#] == {2 n} &], {2}], {n, 36}]] (* _Jayanta Basu_, Jun 28 2013 *)
%t 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 *)
%Y Cf. A000230, A046728.
%K nonn
%O 1,1
%A _Jud McCranie_