The On-Line Encyclopedia of Integer Sequences (OEIS)

Revision History for A039833 (Bold, blue-underlined text is an addition; faded, red-underlined text is a ~~deletion~~.)
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A039833

Smallest of three consecutive squarefree numbers k, k+1, k+2 of the form p*q where p and q are distinct primes.
(history; published version)

#73 by Michael De Vlieger at Sun Sep 29 09:20:34 EDT 2024

STATUS

reviewed

approved

#72 by Joerg Arndt at Sun Sep 29 02:23:44 EDT 2024

STATUS

proposed

reviewed

#71 by Stefano Spezia at Sat Sep 28 09:03:02 EDT 2024

STATUS

editing

proposed

#70 by Stefano Spezia at Sat Sep 28 04:34:36 EDT 2024

REFERENCES

R. K. Guy, Unsolved Problems in Number Theory, Springer, 1st edition, 1981. See section B18.

STATUS

approved

editing

#69 by Peter Luschny at Sun Jan 14 08:58:18 EST 2024

STATUS

reviewed

approved

#68 by Amiram Eldar at Sun Jan 14 07:24:57 EST 2024

STATUS

proposed

reviewed

Discussion

Sun Jan 14

07:29

David A. Corneth: The name is fine. The first comment includes 121 as 121, 122 and 123 all have 4 divisors. so is not equivalent to name. Not sure why Stefanos Mathematica would exclude 121.

07:53

Stefano Spezia: 121 does not have 4 divisors but 3: 1, 11, 121. That is the reason

#67 by Jon E. Schoenfield at Sun Jan 14 07:22:17 EST 2024

STATUS

editing

proposed

#66 by Jon E. Schoenfield at Sun Jan 14 07:20:38 EST 2024

COMMENTS

Cf. A179502 (Numbers n k with the property that nk^2, nk^2+1 and nk^2+2 are all semiprimes). - Zak Seidov, Oct 27 2015

Discussion

Sun Jan 14

07:22

Jon E. Schoenfield: Well, the Name does say “squarefree”, but I do think this is better.

#65 by Jon E. Schoenfield at Sun Jan 14 07:19:43 EST 2024

NAME

Smallest of three consecutive squarefree numbers k, k+1, k+2 of the form p*q where p and q are distinct primes.

STATUS

proposed

editing

#64 by Jon E. Schoenfield at Sun Jan 14 07:13:43 EST 2024

STATUS

editing

proposed

Discussion

Sun Jan 14

07:15

Amiram Eldar: Maybe in Name, "p and q are primes" should be "p and q are distinct primes"? Otherwise, as David says, 121 will also be a term.