OFFSET
1,3
COMMENTS
Possible last three digits of triangular numbers k*(k+1)/2 (leading zeros omitted).
All triangular numbers less than 1000 belong to this sequence. The sequence is finite with 424 terms: a(424)=996 is the last term.
LINKS
Shyam Sunder Gupta, Table of n, a(n) for n = 1..424
EXAMPLE
The last three digits of k*(k+1)/2 can be 000, 001, 003, 021, 140, etc., but not 002, 004, 012, 139 etc.
MATHEMATICA
Union[Table[Mod[n*(n + 1)/2, 1000], {n, 1, 1000}]]
CROSSREFS
KEYWORD
base,fini,full,nonn
AUTHOR
Shyam Sunder Gupta, Aug 30 2013
STATUS
approved