The On-Line Encyclopedia of Integer Sequences (OEIS)

Revision History for A131554 (Bold, blue-underlined text is an addition; faded, red-underlined text is a ~~deletion~~.)
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A131554

Period 5: repeat [1, 1, -1, 1, -1].
(history; published version)

#31 by Joerg Arndt at Tue Dec 12 09:25:21 EST 2023

STATUS

proposed

approved

#30 by Paolo P. Lava at Tue Dec 12 09:23:10 EST 2023

STATUS

editing

proposed

#29 by Paolo P. Lava at Tue Dec 12 09:23:08 EST 2023

FORMULA

a(n) = (1/50)*{-19*(n mod 5)+21*[(n+1) mod 5]-19*[(n+2) mod 5]+21*[(n+3) mod 5]+[(n+4) mod 5]}, with n>=0. - Paolo P. Lava, Aug 28 2007

STATUS

approved

editing

#28 by N. J. A. Sloane at Wed May 22 13:05:02 EDT 2019

KEYWORD

sign,easy,less,changed

STATUS

reviewed

approved

#27 by Peter Luschny at Wed May 22 13:00:53 EDT 2019

STATUS

proposed

reviewed

#26 by Peter Luschny at Wed May 22 13:00:49 EDT 2019

STATUS

editing

proposed

#25 by Peter Luschny at Wed May 22 13:00:41 EDT 2019

FORMULA

a(n) = (-1)^( n+1 - floor(n/5)* 4 - floor((n-1)/5) ). - Mikael Aaltonen May 22 2019

STATUS

proposed

editing

#24 by Mikael Aaltonen at Wed May 22 08:57:39 EDT 2019

STATUS

editing

proposed

Discussion

Wed May 22

10:10

Alois P. Heinz: yes, correct.  But unnecessary.

10:52

Mikael Aaltonen: What do you mean?

11:04

Joerg Arndt: The formula does not convey any insight nor does it give anything of practical use. Kindly stop attempts to add random formulas into the OEIS, this is a waste of the editors' time!

11:06

Alois P. Heinz: any number of formulas producing "repeat [1, 1, -1, 1, -1]" can be given.  But why?

#23 by Mikael Aaltonen at Wed May 22 08:56:28 EDT 2019

FORMULA

a(n) = (-1)^( n +1 - floor( (n-1)/5 )* 4 - floor( (n-21) / 5) ). - Mikael Aaltonen May 22 2019

Discussion

Wed May 22

08:57

Mikael Aaltonen: I shifted it. Correct?

#22 by Alois P. Heinz at Wed May 22 08:45:09 EDT 2019

STATUS

proposed

editing