OFFSET
1,1
EXAMPLE
3 is included since 3-2=1 is a triangular number. 13 is next since 13-3=10 is triangular and 13 has not been used, 10 has not appeared as a difference earlier in the sequence and 5-3,7-3,11-3 are not triangular numbers.
CROSSREFS
KEYWORD
nonn
AUTHOR
Amarnath Murthy, Jul 23 2005
EXTENSIONS
More terms from Matthew Conroy, Mar 28 2006
STATUS
approved