OFFSET
0,5
COMMENTS
20 is the only case where n>3.
EXAMPLE
a(20)=4 since 20=1+3+6+10, a(21)=1 since 21 is triangular, a(22)=2 since 22=1+21, a(23)=-1 since no combination of distinct triangular numbers sum to 23.
CROSSREFS
KEYWORD
sign
AUTHOR
Henry Bottomley, Apr 25 2001
STATUS
approved