A392122 - OEIS

%I #13 Jan 28 2026 22:41:02

%S 3,5,7,13,22,24,25,29,32,39,42,44,45,50,52,56,59,61,62,63,64,65,69,71,

%T 73,75,76,79,81,83,85,86,87,88,89,92,93,94,96,98,100,103,104,105,107,

%U 113,115,123,133,138,139,140,142,143,146,150,153,154,159,163

%N Numbers k such that (k^3 - greatest prime < k^3) > (-k^3 + least prime > k^3).

%C Numbers k such that k^3 is in A264719. - _Robert Israel_, Jan 28 2026

%H Robert Israel, <a href="/A392122/b392122.txt">Table of n, a(n) for n = 1..10000</a>

%p g:= proc(n) nextprime(n) + prevprime(n) < 2*n end proc:

%p select(k -> g(k^3), [$2..200]); # _Robert Israel_, Jan 28 2026

%t z = 600; f[x_] := f[x] = x^3;

%t u[n_] := NextPrime[f[n], -1]; v[n_] := NextPrime[f[n]];

%t s1 = Select[Range[z], f[#] - v[#] < u[#] - f[#] &]   (* A392120 *)

%t s2 = Select[Range[z], f[#] - v[#] == u[#] - f[#] &]  (* A075191 *)

%t s3 = Select[Range[z], f[#] - v[#] > u[#] - f[#] &]   (* A392122 *)

%Y Cf. A264719, A390788, A392120, A392121.

%K nonn

%O 1,1

%A _Clark Kimberling_, Jan 18 2026

%E 1 removed by _Sean A. Irvine_, Jan 28 2026