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Revision History for A187126 (Bold, blue-underlined text is an addition; faded, red-underlined text is a deletion.)

Showing entries 1-10 | older changes
A187126
Triangular numbers k*(k+1)/2 mod 1000, sorted and uniqued.
(history; published version)
#18 by Andrew Howroyd at Wed May 19 21:01:12 EDT 2021
STATUS

proposed

approved

#17 by Jon E. Schoenfield at Wed May 19 20:53:48 EDT 2021
STATUS

editing

proposed

#16 by Jon E. Schoenfield at Wed May 19 20:53:45 EDT 2021
NAME

Triangular numbers nk*(nk+1)/2 mod 1000, sorted and uniqued.

COMMENTS

Possible last three digits of triangular numbers nk*(nk+1)/2 (leading zeros omitted).

All triangular numbers less than 1000 belong to this sequence; the . The sequence is finite with 424 terms: a(424)=996 is the last term.

EXAMPLE

The last three digits of nk*(nk+1)/2 can be: 000, 001, 003, 021, 140, etc... , but not 002, 004, 012, 139 etc...

STATUS

approved

editing

#15 by T. D. Noe at Sun Sep 01 14:14:13 EDT 2013
STATUS

editing

approved

#14 by T. D. Noe at Sun Sep 01 14:14:07 EDT 2013
NAME

Triangular numbers n*(n+1)/2 mod 1000, sorted and uniqued.

STATUS

approved

editing

#13 by T. D. Noe at Sun Sep 01 14:03:35 EDT 2013
STATUS

editing

approved

#12 by T. D. Noe at Sun Sep 01 14:03:30 EDT 2013
CROSSREFS

Cf. A000217, A122986.

STATUS

approved

editing

#11 by T. D. Noe at Sun Sep 01 14:02:33 EDT 2013
STATUS

proposed

approved

#10 by Shyam Sunder Gupta at Fri Aug 30 14:14:32 EDT 2013
STATUS

editing

proposed

Discussion
Sat Aug 31
02:47
Joerg Arndt: random parameter
04:48
Shyam Sunder Gupta: not clear . please elaborate.
Sun Sep 01
13:25
Joerg Arndt: You could use the modulus 239 as well.  What makes 1000 interesting?
14:02
T. D. Noe: I take back what I wrote earlier; I approve this.
14:04
Shyam Sunder Gupta: Mod 1000 is interesting as it gives possible three digit endings of triangular numbers. Mere looking at results(b-file) many interesting results can be seen.
#9 by Shyam Sunder Gupta at Fri Aug 30 14:14:08 EDT 2013
LINKS

Shyam Sunder Gupta, <a href="/A187126/b187126.txt">Table of n, a(n) for n = 1..424</a>

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