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A187127 Triangular numbers n*(n+1)/2 mod 100, sorted and uniqued. 5
0, 1, 3, 5, 6, 10, 11, 15, 16, 20, 21, 25, 26, 28, 30, 31, 35, 36, 40, 41, 45, 46, 50, 51, 53, 55, 56, 60, 61, 65, 66, 70, 71, 75, 76, 78, 80, 81, 85, 86, 90, 91, 95, 96 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,3

COMMENTS

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

All triangular numbers less than 100 belong to this sequence; the sequence is finite with 44 terms: a(44)=96 is the last term.

LINKS

Table of n, a(n) for n=1..44.

EXAMPLE

The last two digits of n*(n+1)/2  can be: 00, 01, 03, 20, 91, etc... but not 02, 04, 12, 97 etc...

MATHEMATICA

Union[Table[Mod[n*(n + 1)/2, 100], {n, 1, 100}]]

CROSSREFS

Cf. A000217, A010461.

Sequence in context: A175304 A140951 A190243 * A187126 A065873 A072282

Adjacent sequences:  A187124 A187125 A187126 * A187128 A187129 A187130

KEYWORD

base,fini,full,nonn

AUTHOR

Shyam Sunder Gupta, Aug 30 2013

STATUS

approved

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Last modified February 21 23:41 EST 2020. Contains 332113 sequences. (Running on oeis4.)