login
a(n) = A257851(n,n).
13

%I #16 Feb 19 2022 01:34:08

%S 1,9,27,80,216,448,1296,2816,6400,13312,30720,62208,139264,311296,

%T 688128,1474560,2985984,6029312,12845056,30408704,65011712,131072000,

%U 264241152,553648128,1132462080,2293235712,4697620480,9932111872,20132659200,41875931136,88046829568

%N a(n) = A257851(n,n).

%t a[n_] := a[n] = Reap[For[m = 1; k = 1, k <= n+1, If[PrimeOmega[m] - PrimeNu[m] == n, Sow[m]; k++]; m++]][[2, 1]] // Last;

%t Table[Print[n, " ", a[n]]; a[n], {n, 0, 20}] (* _Jean-François Alcover_, Oct 03 2021 *)

%o (Haskell)

%o a264959 n = a257851 n n

%o (PARI) a(n) = my(nb=0, k=1); until (nb == n+1, my(f=factor(k)); if (bigomega(f) - omega(f) == n, nb++); k++;); k-1; \\ _Michel Marcus_, Feb 05 2022

%Y Cf. A046660, A257851, A261256.

%K nonn

%O 0,2

%A _Reinhard Zumkeller_, Nov 29 2015

%E a(21)-a(25) from _Michel Marcus_, Feb 05 2022

%E More terms from _Jinyuan Wang_, Feb 18 2022