A075039 Smallest of three consecutive squarefree numbers having equal numbers of prime factors.

33, 85, 93, 141, 201, 213, 217, 301, 393, 445, 633, 697, 921, 1041, 1137, 1261, 1309, 1345, 1401, 1641, 1761, 1837, 1885, 1893, 1941, 1981, 2013, 2101, 2181, 2217, 2305, 2361, 2433, 2461, 2517, 2641, 2665, 2721, 2733, 3097, 3385, 3601, 3693, 3729, 3865

Offset

1,1

Links

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

Formula

A001221(a(n)) = A001222(a(n)) = A001221(a(n)+1) = A001222(a(n)+1).

Example

33 is a member as 33, 34 and 35 are of the form p*q where p and q are primes.

Mathematica

Select[Range[4000], AllTrue[# + Range[0, 2], SquareFreeQ] && Equal @@ PrimeNu[# + Range[0, 2]] &] (* Amiram Eldar, Feb 24 2021 *)

Crossrefs

Cf. A001221, A001222, A005117, A052214, A086263, A039833.

Sequence in context: A005238 A052214 A063838 * A359746 A039833 A355711

Adjacent sequences: A075036 A075037 A075038 * A075040 A075041 A075042

Keyword

nonn

Author

Amarnath Murthy, Sep 03 2002

Extensions

More terms from Matthew Conroy, Sep 08 2002

Edited by Reinhard Zumkeller, Jul 14 2003

Offset corrected by Amiram Eldar, Feb 24 2021

Status

approved