A264959 a(n) = A257851(n,n).

1, 9, 27, 80, 216, 448, 1296, 2816, 6400, 13312, 30720, 62208, 139264, 311296, 688128, 1474560, 2985984, 6029312, 12845056, 30408704, 65011712, 131072000, 264241152, 553648128, 1132462080, 2293235712, 4697620480, 9932111872, 20132659200, 41875931136, 88046829568

Offset: 0

Author

Reinhard Zumkeller, Nov 29 2015

Keywords

• nonn

Crossrefs

Cf. A046660, A257851, A261256.

Programs

Haskell

a264959 n = a257851 n n

Mathematica

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;
Table[Print[n, " ", a[n]]; a[n], {n, 0, 20}] (* Jean-François Alcover, Oct 03 2021 *)

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

Extensions

a(21)-a(25) from Michel Marcus, Feb 05 2022

More terms from Jinyuan Wang, Feb 18 2022