The On-Line Encyclopedia of Integer Sequences (OEIS)

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Revision History for A109613 (Bold, blue-underlined text is an addition; faded, red-underlined text is a ~~deletion~~.)
Showing entries 1-10 | older changes

Odd numbers repeated.
(history; published version)

#149 by Joerg Arndt at Thu Feb 08 01:41:10 EST 2024

STATUS

editing

approved

#148 by Paolo P. Lava at Wed Feb 07 16:35:47 EST 2024

COMMENTS

Its ordinal transform is A000034. - Paolo P. Lava, Jun 25 2009

FORMULA

a(n) = n + (1 + (-1)^n)/2. - Paolo P. Lava, May 08 2007

STATUS

approved

editing

#147 by Sean A. Irvine at Tue Dec 19 14:58:34 EST 2023

STATUS

proposed

approved

#146 by Torlach Rush at Tue Nov 14 17:21:10 EST 2023

STATUS

editing

proposed

Discussion

Wed Nov 15

00:37

Michel Marcus: same as 1st formula ??

00:37

Michel Marcus: ubiquity of floor : nivellemment par le bas ?

01:08

Michel Marcus: just a joke

Thu Nov 16

21:07

Torlach Rush: Ripost

21:09

Torlach Rush: The joke falls flat.:-)

Thu Nov 23

21:30

Torlach Rush: @Michel Marcus: every formula after the 1st formula reduces to the 1st formula. This is the first formula that introduces the triangular numbers. Regards.

Tue Dec 19

14:58

Sean A. Irvine: Pretty marginal utility, but lets keep it.

#145 by Joerg Arndt at Fri Nov 10 23:07:48 EST 2023

STATUS

proposed

editing

Discussion

Tue Nov 14

16:22

Torlach Rush: a(1) = A000217(1) / A004526(2) = 1/1 = 1
a(2) = A000217(2) / A004526(3) = 3/1 = 3
a(3) = A000217(3) / A004526(4) = 6/2 = 3
a(4) = A000217(4) / A004526(5) = 10/2 = 5
...
The equation highlights the ubiquity and importance of the floor() function.

#144 by Torlach Rush at Fri Nov 10 15:28:54 EST 2023

STATUS

editing

proposed

Discussion

Fri Nov 10

23:07

Joerg Arndt: cannot verify; also: what is the point?

#143 by Torlach Rush at Fri Nov 10 15:26:23 EST 2023

FORMULA

a(n) = A000217(n) / A004536A004526(n+1), n > 0. - Torlach Rush, Nov 10 2023

#142 by Torlach Rush at Fri Nov 10 15:25:34 EST 2023

FORMULA

a(n) = A000217(n) / A004536(n+1), n > 0. - Torlach Rush, Nov 10 2023

CROSSREFS

Cf. A000217, A063196, A110660, A186421, A186422, A211955, A230584, A290988.

STATUS

approved

editing

#141 by R. J. Mathar at Sat Feb 25 14:12:52 EST 2023

STATUS

editing

approved

#140 by R. J. Mathar at Sat Feb 25 13:50:22 EST 2023

COMMENTS

The binomial transform is 1, 2, 6, 16, 40, 96, 224, 512, 1152, 2560,.. (see A057711). - R. J. Mathar, Feb 25 2023

STATUS

approved

editing