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A187127
Triangular numbers k*(k+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
OFFSET
1,3
COMMENTS
Possible last two digits of triangular numbers k*(k+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.
EXAMPLE
The last two digits of k*(k+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
Sequence in context: A175304 A140951 A190243 * A187126 A065873 A072282
KEYWORD
base,fini,full,nonn
AUTHOR
Shyam Sunder Gupta, Aug 30 2013
STATUS
approved