The On-Line Encyclopedia of Integer Sequences (OEIS)

Revision History for A299761

(Bold, blue-underlined text is an addition; faded, red-underlined text is a ~~deletion~~.)
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A299761

Irregular triangle read by rows: T(n,k), n >= 1, k >= 1, in which row n lists the middle divisors of n, or 0 if there are no middle divisors of n.
(history; published version)

#43 by Peter Luschny at Thu Aug 04 05:04:38 EDT 2022

STATUS

reviewed

approved

#42 by Hugo Pfoertner at Thu Aug 04 05:00:37 EDT 2022

STATUS

proposed

reviewed

#41 by Michel Marcus at Thu Aug 04 03:07:42 EDT 2022

STATUS

editing

proposed

#40 by Michel Marcus at Thu Aug 04 03:03:54 EDT 2022

PROG

(PARI) row(n) = my(v=select(x->((x >= sqrt(n/2)) && (x < sqrt(n*2))), divisors(n))); if (#v, v, [0]); \\ Michel Marcus, Aug 04 2022

STATUS

approved

editing

#39 by N. J. A. Sloane at Wed Jun 22 20:33:49 EDT 2022

STATUS

proposed

approved

#38 by Omar E. Pol at Tue Jun 21 14:00:45 EDT 2022

STATUS

editing

proposed

#37 by Omar E. Pol at Tue Jun 21 14:00:29 EDT 2022

NAME

Irregular triangle read by rows : T(n,k), n >= 1, k >= 1, in which row n lists the middle divisors of n, or 0 if there are no middle divisors of n.

STATUS

proposed

editing

Discussion

Tue Jun 21

14:00

Omar E. Pol: Improvements in the Name.

#36 by Omar E. Pol at Tue Jun 21 13:57:45 EDT 2022

STATUS

editing

proposed

#35 by Omar E. Pol at Tue Jun 21 13:57:06 EDT 2022

EXAMPLE

For n = 72 the middle divisors of 72 are 6, 8 and 9, so row 72 is [6, 8, 9].

STATUS

approved

editing

Discussion

Tue Jun 21

13:57

Omar E. Pol: Added an example. I think the signature is not necessary.

#34 by Amiram Eldar at Fri Jun 17 06:06:31 EDT 2022

STATUS

reviewed

approved