A095390 - OEIS

%I #6 Oct 15 2013 22:32:25

%S 64,28,11,14,5,3,2,1,968

%N Least inverse of A095389.

%C It is believed (or proved) that values at n > 8 indices do not occur, except once, at the beginning when 13 lesser twins in 210.0+R range, where R is the reduced residues modulo 210.

%F a(n) = min{x: A095389(x) = n}

%e a(13) = 0 because A095389(0) = 13.

%e a(1) = 28 means that in reduced residue system 210.28+R exactly 1 lesser-twin-prime arises; see A095389.

%e a(8) = 968 means that at surprisingly high density of twin primes [8 cases] occur in range of {210.968+r, 210.968+r+2}, as follows: {203309, 203321, 203339, 203351, 203381, 203417, 203429, 203459}.

%t {k=0, ta=Table[0, {100000}]}; Do[{m=0};Do[s=210k+r; s1=210k+r+2; If[PrimeQ[s]&&PrimeQ[s+2], m=m+1], {r, 1, 210}];ta[[k]]=m, {k, 1, 100000}]; Table[Min[Flatten[Position[ta, j]]], {j, 0, 15}]

%Y Cf. A095389, A078859.

%K fini,nonn

%O 0,1

%A _Labos Elemer_, Jun 16 2004

%E Edited by _Charles R Greathouse IV_, Oct 27 2010