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Revision History for A244579 (Bold, blue-underlined text is an addition; faded, red-underlined text is a deletion.)

Showing entries 1-10 | older changes
Numbers n with the property that the number of parts in the symmetric representation of sigma(n) equals the number of divisors of n.
(history; published version)
#68 by N. J. A. Sloane at Thu Apr 28 13:41:22 EDT 2022
STATUS

proposed

approved

#67 by Omar E. Pol at Sun Apr 17 18:51:40 EDT 2022
STATUS

editing

proposed

#66 by Omar E. Pol at Sun Apr 17 18:50:59 EDT 2022
COMMENTS

A090196 is a complement of this sequence in the set of odd numbers. - Hartmut F. W. Hoft, Dec 10 2016 [simplified by Omar E. Pol, Apr 17 2022]

STATUS

proposed

editing

Discussion
Sun Apr 17
18:51
Omar E. Pol: Removed the comment because it was a duplicate of the above comment.
#65 by Omar E. Pol at Sun Apr 17 18:29:52 EDT 2022
STATUS

editing

proposed

#64 by Omar E. Pol at Sun Apr 17 18:29:43 EDT 2022
COMMENTS

Let n = 2^m * q with m >= 0 and q odd. Let c_n denote the count of regions in the symmetric representation of sigma(n), which is determined by the positions of 1's in the n-th row of A237048. The maximum of c_n occurs when odd and even positions of 1's alternate implying that all regions have width 1, denoted by w_n = 1. When m > 0 then sigma_0(n) > sigma_0(q) and c_n = sigma_0(n) is impossible. Therefore, exactly those odd n with w_n = 1 are in this sequence. Furthermore, since the 1's in A237048 represent the odd divisors of n, their odd-even alternation expresses the property 2*f < g for any two adjacent divisors f < g of odd number n; in other words, this sequence is also the complement of A090196 relative to the odd numbers (see also A244969). This last property permits computations of elements in this sequence faster than with function a244579, which is based on Dyck paths. - Hartmut F. W. Hoft, Oct 11 2015

STATUS

proposed

editing

#63 by Omar E. Pol at Sun Apr 17 18:28:59 EDT 2022
STATUS

editing

proposed

#62 by Omar E. Pol at Sun Apr 17 18:27:59 EDT 2022
COMMENTS

A090196 is a complement of this sequence in the set of odd numbers. - Hartmut F. W. Hoft, Dec 10 2016 [simplified by Omar E. Pol, Apr 17 2022]

Discussion
Sun Apr 17
18:28
Omar E. Pol: Simplified a comment since A244969 is a duplicate of  A090196.
#61 by Omar E. Pol at Sun Apr 17 18:27:28 EDT 2022
COMMENTS

Since A244969 also A090196 is a complement of this sequence in the set of odd numbers this shows that A244969 = A090196. - Hartmut F. W. Hoft, Dec 10 2016 [simplified by _Omar E. Pol_, Apr 17 2022

STATUS

approved

editing

#60 by Joerg Arndt at Sun Jun 03 03:39:17 EDT 2018
STATUS

proposed

approved

#59 by Jon E. Schoenfield at Sun Jun 03 02:27:43 EDT 2018
STATUS

editing

proposed