A391356 Numbers k such that 4*k - (greatest prime < 4*k) > (least prime > 4*k) - 4*k.

4, 7, 9, 10, 13, 22, 24, 25, 28, 31, 34, 37, 39, 43, 47, 49, 52, 55, 58, 62, 64, 67, 69, 70, 73, 76, 79, 82, 84, 86, 88, 91, 93, 97, 99, 100, 102, 104, 107, 112, 114, 115, 119, 121, 124, 127, 129, 130, 134, 135, 139, 142, 144, 146, 148, 153, 154, 157, 160

Offset

1,1

Links

Table of n, a(n) for n=1..59.

Mathematica

z = 1500; f[x_] := f[x] = 4*x;
u[n_] := NextPrime[f[n], -1]; v[n_] := NextPrime[f[n]];
Select[Range[400], m*# - v[#] < u[#] - m*# &]    (* A391354 *)
Select[Range[400], m*# - v[#] == u[#] - m*# &]   (* A391355 *)
Select[Range[400], m*# - v[#] > u[#] - m*# &]    (* A391356 *)

Crossrefs

Cf. A000027, A000040, A391351, A391354, A391355.

Sequence in context: A010442 A055047 A234429 * A291201 A310940 A342839

Adjacent sequences: A391353 A391354 A391355 * A391357 A391358 A391359

Keyword

nonn

Author

Clark Kimberling, Dec 18 2025

Status

approved