A391352 Numbers k such that 3*k - (greatest prime < 3*k) = (least prime > 3*k) - 3*k.

2, 3, 4, 5, 6, 7, 10, 13, 14, 15, 20, 23, 24, 27, 31, 33, 34, 35, 36, 37, 40, 43, 46, 48, 50, 55, 60, 62, 64, 65, 66, 75, 76, 77, 80, 82, 90, 93, 94, 96, 100, 103, 104, 105, 108, 114, 116, 117, 121, 127, 131, 133, 135, 138, 140, 142, 144, 147, 151, 153, 154

Offset

1,1

Links

Table of n, a(n) for n=1..61.

Mathematica

m = 3; z = 140;
u[n_] := NextPrime[m n, -1]; v[n_] := NextPrime[m n];
Select[Range[400], m*# - v[#] < u[#] - m*# &]   (* A391351 *)
Select[Range[400], m*# - v[#] == u[#] - m*# &]  (* A391352 *)
Select[Range[400], m*# - v[#] > u[#] - m*# &]   (* A391353 *)

Crossrefs

Cf. A000040, A391351, A391353.

Sequence in context: A164947 A112881 A389645 * A308019 A008814 A005140

Adjacent sequences: A391349 A391350 A391351 * A391353 A391354 A391355

Keyword

nonn

Author

Clark Kimberling, Dec 10 2025

Status

approved