A078859 Least positive residues (mod 210) representing those residue classes which can be the lesser of twin prime pairs (A001359).

3, 5, 11, 17, 29, 41, 59, 71, 101, 107, 137, 149, 167, 179, 191, 197, 209

Offset

1,1

Links

Table of n, a(n) for n=1..17.

Formula

Intersection[RRS(210), 2+RRS{210)]-2 and {3, 5}. RRS(210)=reduced residue system of 210=first 48=phi(210) terms of A008364; two additional term 3 and 5 are singular cases; 210k+r generates complete A001359 with suitable k and r taken from these 15+2 numbers.

Mathematica

With[{n = 4}, Function[P, Join[Select[Prime@ Range@ n, NextPrime@ # == # + 2 &], Select[Partition[Select[Range[P + 1], CoprimeQ[#, P] &], 2, 1], Differences@ # == {2} &][[All, 1]]]]@ Product[Prime@ i, {i, n}]] (* Michael De Vlieger, May 15 2017 *)

Crossrefs

Cf. A001359, A008364.

Sequence in context: A069233 A329946 A063700 * A054799 A093326 A001359

Adjacent sequences: A078856 A078857 A078858 * A078860 A078861 A078862

Keyword

fini,full,nonn

Author

Labos Elemer, Dec 13 2002

Status

approved