A342258 Numbers k such that Omega(k-1) = Omega(k)-1 and Omega(k+1) = Omega(k)+1, where Omega is the number of prime divisors counted with multiplicity, A001222.

62, 74, 188, 194, 195, 275, 278, 363, 398, 422, 423, 483, 494, 495, 614, 662, 663, 747, 758, 764, 782, 867, 1028, 1071, 1094, 1095, 1235, 1238, 1268, 1394, 1419, 1454, 1658, 1659, 1682, 1844, 1910, 1916, 1955, 1970, 2043, 2067, 2138, 2139, 2223, 2235, 2247, 2259

Offset: 1

Author

Hugo Pfoertner, Mar 07 2021

Keywords

• nonn

Links

• Hugo Pfoertner, Table of n, a(n) for n = 1..10001

Crossrefs

Cf. A001222, A342259.

Programs

Mathematica

seq[nmax_] := Module[{om}, om[n_] := om[n] = PrimeOmega[n]; Select[Range[2, nmax], om[# - 1] == om[#] - 1 && om[# + 1] == om[#] + 1 &]]; seq[2500] (* Amiram Eldar, Sep 19 2024 *)

PARI

for(n=3,2300,my(bO=bigomega(n));if(bigomega(n-1)==bO-1&&bigomega(n+1)==bO+1,print1(n,", ")))