login
The OEIS Foundation is supported by donations from users of the OEIS and by a grant from the Simons Foundation.

 

Logo


Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A075039 Smallest of three consecutive squarefree numbers having equal numbers of prime factors. 3
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 (list; graph; refs; listen; history; text; internal format)
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 * A039833 A250732 A080700

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

Lookup | Welcome | Wiki | Register | Music | Plot 2 | Demos | Index | Browse | More | WebCam
Contribute new seq. or comment | Format | Style Sheet | Transforms | Superseeker | Recent
The OEIS Community | Maintained by The OEIS Foundation Inc.

License Agreements, Terms of Use, Privacy Policy. .

Last modified April 20 18:08 EDT 2021. Contains 343135 sequences. (Running on oeis4.)