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

1,1

Links

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

Example

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

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 *)

Crossrefs

Cf. A076136, A001222.

Sequence in context: A275713 A114076 A078092 * A138340 A113250 A329910

Adjacent sequences: A076134 A076135 A076136 * A076138 A076139 A076140

Keyword

nonn

Author

Joseph L. Pe, Oct 30 2002

Status

approved