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

1,1

Links

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

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 *)

Prog

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

Crossrefs

Cf. A001222, A342259.

Sequence in context: A138172 A074772 A074771 * A039391 A043214 A043994

Adjacent sequences: A342255 A342256 A342257 * A342259 A342260 A342261

Keyword

nonn

Author

Hugo Pfoertner, Mar 07 2021

Status

approved