A076153 Numbers n such that Omega(n) = Omega(n-1)^2, where Omega(m) (A001222) denotes the number of prime factors of m, counted with multiplicity.

3, 16, 36, 40, 56, 88, 135, 156, 184, 204, 210, 220, 248, 250, 260, 296, 306, 315, 328, 330, 340, 342, 372, 414, 459, 472, 490, 516, 536, 546, 580, 584, 636, 650, 686, 690, 708, 714, 732, 735, 738, 804, 808, 819, 836, 850, 852, 870, 872, 940, 950, 966, 975, 996, 999

Offset

1,1

Links

Amiram Eldar, Table of n, a(n) for n = 1..10000

Example

Omega(996) = 2^2 = Omega(995)^2, so 996 is a term of the sequence.

Mathematica

Select[Range[1000], PrimeOmega[#]==PrimeOmega[#-1]^2&] (* Ray Chandler, Jul 07 2015 *)
Flatten[Position[Partition[PrimeOmega[Range[1000]], 2, 1], _?(#[[1]]^2==#[[2]]&), 1, Heads-> False]]+ 1 (* Harvey P. Dale, Nov 05 2023 *)

Crossrefs

Similar to A109287; after a(1)=3 next difference is a(101)=1792 whereas A109287(100)=1794. - Ray Chandler, Mar 20 2007

Cf. A001222.

Sequence in context: A162419 A322191 A359559 * A031302 A217130 A173390

Adjacent sequences: A076150 A076151 A076152 * A076154 A076155 A076156

Keyword

easy,nonn

Author

Joseph L. Pe, Oct 31 2002

Extensions

Edited by Ray Chandler, Mar 20 2007

Status

approved