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The On-Line Encyclopedia of Integer Sequences (OEIS)
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Revision History for A100683

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

Showing entries 1-10 | older changes
a(n) = a(n-1) + a(n-2) + a(n-3); a(0) = -1, a(1) = 2, a(2) = 2.
(history; published version)
#49 by Peter Luschny at Fri Jul 01 12:20:15 EDT 2022
STATUS

reviewed

approved

#48 by Joerg Arndt at Fri Jul 01 11:07:24 EDT 2022
STATUS

proposed

reviewed

#47 by Michel Marcus at Mon Jun 20 12:03:24 EDT 2022
STATUS

editing

proposed

#46 by Michel Marcus at Mon Jun 20 12:03:11 EDT 2022
COMMENTS

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|_|_____|_|___|_|. (End)

STATUS

proposed

editing

#45 by Greg Dresden at Tue Jun 14 22:52:48 EDT 2022
STATUS

editing

proposed

Discussion
Tue Jun 14
23:36
Jon E. Schoenfield: Thanks!
#44 by Greg Dresden at Tue Jun 14 22:52:19 EDT 2022
COMMENTS

For n >= 2, a(n+2) is the number of ways to tile this figure of length n with squares, dominos, dominoes, and "trominostrominoes" (of length 3):

As an example, here is one of the 254 possible tilings of this figure of length 8 with squares, dominos, dominoes, and trominostrominoes:

STATUS

proposed

editing

Discussion
Tue Jun 14
22:52
Greg Dresden: Done!
#43 by Michel Marcus at Tue Jun 14 10:38:03 EDT 2022
STATUS

editing

proposed

Discussion
Tue Jun 14
21:44
Jon E. Schoenfield: Please change “dominos” and “trominos” to “dominoes” and “trominoes”.  Thanks!
#42 by Michel Marcus at Tue Jun 14 10:37:52 EDT 2022
COMMENTS

From Greg Dresden and Veda Garigipati, Jun 14 2022: (Start)

|_|_____|_|___|_|. - Greg Dresden and Veda Garigipati, Jun 14 2022

|_|_____|_|___|_|. (End)

LINKS

Martin Burtscher, Igor Szczyrba, and Rafał Szczyrba, <a href="http://www.emis.de/journals/JIS/VOL18/Szczyrba/sz3.html">Analytic Representations of the n-anacci Constants and Generalizations Thereof</a>, Journal of Integer Sequences, Vol. 18 (2015), Article 15.4.5.

CROSSREFS

Cf. A001590, A020992.

Cf. A000073.

STATUS

proposed

editing

#41 by Greg Dresden at Tue Jun 14 10:30:19 EDT 2022
STATUS

editing

proposed

#40 by Greg Dresden at Tue Jun 14 10:29:29 EDT 2022
COMMENTS

For n >= 2, a(n+2) is the number of ways to tile this figure of length n with squares, dominos, and "trominos" (of length 3):

.___

|_|_|____________

|_|_|_|_|_|_|_|_|

As an example, here is one of the 254 possible tilings of this figure of length 8 with squares, dominos, and trominos:

.___

| |_|____________

|_|_____|_|___|_|. - Greg Dresden and Veda Garigipati, Jun 14 2022