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Revision History for A061059

(Bold, blue-underlined text is an addition; faded, red-underlined text is a deletion.)

Showing entries 1-10 | older changes
#22 by N. J. A. Sloane at Thu Apr 04 23:50:00 EDT 2019
STATUS

editing

approved

#21 by N. J. A. Sloane at Thu Apr 04 23:49:58 EDT 2019
DATA

2, 3, 6, 15, 55, 182, 715, 3135, 15015, 81345, 448630, 2733549, 17490603, 114388729, 785147363, 5708795638, 43850489690, 342503171205, 2803419704514, 23622001517543, 201817933409378, 1793779635410490, 16342166369958702

COMMENTS

Previous name was: Write product of first n primes as x*y with x<y and x maximal; sequence gives value of y.

Is this the same as A060796? - R. J. Mathar, Oct 02 2008

Yes: primorial(n) = A002110(n) = Pn# is never a square, it has N=2^n distinct divisors. This is an even number, and the N divisors can be grouped in pairs d(k), d(N+1-k) with product equal to Pn#, and one being smaller and one being larger than sqrt(Pn#). This sequence gives the (2^(n-1)+1)-th divisor, which is the smallest one larger than sqrt(Pn#). - M. F. Hasler, Sep 20 2011

EXAMPLE

2*3*5*7 = 210 = 14*15 with difference of 1.

CROSSREFS
AUTHOR

Ed Pegg Jr, May 28 2001

EXTENSIONS

Terms 16 through 37 computed by Jud McCranie, Apr 15 2000

Under construction, do not touch

STATUS

approved

editing

#20 by N. J. A. Sloane at Thu Apr 04 23:46:26 EDT 2019
STATUS

editing

approved

#19 by N. J. A. Sloane at Thu Apr 04 23:46:16 EDT 2019
EXTENSIONS

Under construction, do not touch

STATUS

proposed

editing

#18 by M. F. Hasler at Wed Apr 03 17:56:02 EDT 2019
STATUS

editing

proposed

Discussion
Wed Apr 03
18:00
M. F. Hasler: PS: actually, it was considered dead already back then, in a comment in A060796.
#17 by M. F. Hasler at Wed Apr 03 17:55:55 EDT 2019
COMMENTS

Is this the same as A060796? [_- _R. J. Mathar_, Oct 02 2008]

STATUS

proposed

editing

Discussion
Wed Apr 03
17:56
M. F. Hasler: OK, I'll do. Funny, that this has been "certified" duplicate in 2011 and only now "killed". I hope the comments can remain there (or else it should be merged into A060796.
#16 by Joerg Arndt at Sun Mar 31 03:36:06 EDT 2019
STATUS

editing

proposed

Discussion
Sun Mar 31
03:38
Michel Marcus: should we ask Maximilian to make a bfile in A060796 ?
#15 by Joerg Arndt at Sun Mar 31 03:35:52 EDT 2019
NAME

Write product of first n primes as x*y with x<y and x maximal; sequence gives value of y.

Duplicate of A060796.

COMMENTS

Previous name was: Write product of first n primes as x*y with x<y and x maximal; sequence gives value of y.

KEYWORD

nonn,changed

dead

STATUS

reviewed

editing

#14 by Joerg Arndt at Sun Mar 31 03:34:09 EDT 2019
STATUS

proposed

reviewed

#13 by Michel Marcus at Sun Mar 31 03:33:26 EDT 2019
STATUS

editing

proposed