A076137 Numbers k such that Omega(k) = Omega(k-1) + Omega(k-2) + Omega(k-3), where Omega(n) denotes the number of prime factors of n, with multiplicity.

4, 32, 64, 96, 144, 180, 216, 224, 240, 360, 400, 432, 576, 600, 648, 672, 800, 972, 1008, 1040, 1088, 1104, 1188, 1232, 1260, 1344, 1400, 1404, 1408, 1456, 1500, 1584, 1620, 1624, 1680, 1700, 1764, 1800, 1840, 1880, 1904, 1920, 1980, 2000, 2040, 2064

Offset: 1

Author

Joseph L. Pe, Oct 30 2002

Keywords

• nonn

Examples

			a(3) = 64 is a term because Omega(64) = 6 = Omega(63)+Omega(62)+Omega(61) = 3+2+1 = 6.
		

Links

• Harvey P. Dale, Table of n, a(n) for n = 1..1000

Crossrefs

Cf. A076136, A001222.

Programs

Mathematica

l = {4}; Do[If[Omega[n] == Omega[n - 1] + Omega[n - 2] + Omega[n - 3], l = Append[l, n]], {n, 5, 5000}]; l
Transpose[Select[Partition[Range[2100],4,1],PrimeOmega[Last[#]] == Total[ PrimeOmega[Take[#,3]]]&]][[4]] (* Harvey P. Dale, Nov 29 2011 *)