A220144 The values of k in A220143.

4, 6, 9, 18, 24, 42, 54, 120, 258, 396, 420, 594, 744, 840, 1074, 1800, 2130, 2172, 2256, 2304, 2550, 2778, 3282, 3792, 3894, 4170, 4488, 4578, 4626, 4848, 5562, 5754, 6192, 6252, 7260, 7428, 7920, 9654

Offset: 1

Author

T. D. Noe, Jan 08 2013

Keywords

• nonn
• more

Crossrefs

Cf. A071558, A220143.

Programs

Mathematica

t = {{1, 4}}; Do[k = 1; While[! (PrimeQ[k*n - 1] && PrimeQ[k*n + 1]), k++]; If[k > t[[-1, 2]], AppendTo[t, {n, k}]], {n, 2, 100000}]; Transpose[t][[2]]

Extensions

More terms from Amiram Eldar, Dec 30 2019