The On-Line Encyclopedia of Integer Sequences (OEIS)

Revision History for A179070 (Bold, blue-underlined text is an addition; faded, red-underlined text is a ~~deletion~~.)
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A179070

a(1)=a(2)=a(3)=1, a(4)=3; thereafter a(n) = a(n-1) + a(n-3).
(history; published version)

#49 by R. J. Mathar at Sun May 19 13:25:06 EDT 2024

STATUS

editing

approved

#48 by R. J. Mathar at Sun May 19 13:24:59 EDT 2024

FORMULA

a(n) = A000930(n-2)+2*A000930(n-4) for n>3. - R. J. Mathar, May 19 2024

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approved

editing

#47 by Michel Marcus at Sun Jun 14 01:58:39 EDT 2020

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reviewed

approved

#46 by Joerg Arndt at Sun Jun 14 01:31:05 EDT 2020

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proposed

reviewed

#45 by Wesley Ivan Hurt at Sat Jun 13 18:38:39 EDT 2020

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editing

proposed

#44 by Wesley Ivan Hurt at Sat Jun 13 18:38:28 EDT 2020

COMMENTS

a(n+1) is the number of multus bitstrings of length n with no runs of 2 zeroes0's. - Steven Finch, Mar 25 2020

For n > = 5, a(n) gives the number of ways to tile the following board of length n-3 with squares and trominos:

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proposed

editing

#43 by Michel Marcus at Sat Jun 13 12:23:38 EDT 2020

STATUS

editing

proposed

#42 by Michel Marcus at Sat Jun 13 12:23:35 EDT 2020

COMMENTS

Column sums of shifted (1,2) Pascal array:

From Areebah Mahdia and Greg Dresden, Jun 13 2020: (Start)

|_|_|_|_|_|_|_| ... . - Areebah Mahdia and Greg Dresden, Jun 13 2020

|_|_|_|_|_|_|_| ... . (End)

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proposed

editing

#41 by Greg Dresden at Sat Jun 13 10:51:20 EDT 2020

STATUS

editing

proposed

#40 by Greg Dresden at Sat Jun 13 10:50:39 EDT 2020

COMMENTS

For n > = 5, a(n) gives the number of ways to tile the following board of length n-3 with squares and trominos:

._ _

|_|_|

|_|_|_ _ _ _ _

|_|_|_|_|_|_|_| ... . - Areebah Mahdia and Greg Dresden, Jun 13 2020

STATUS

approved

editing