OFFSET
1,7
EXAMPLE
1=1^2 so a(1)=1, 2=1^2+1^2 so a(2)=1 and a(3)=1, 3=1^2+1^2+1^2 so a(4)=1 and a(5)=1 and a(6)=1, 4=2^2 so a(7)=2, 5=1^2+2^2 so a(8)=1 and a(9)=2, 6=1^2+1^2+2^2 so a(10)=1 and a(11)=1 and a(12)=2, 7=1^2+1^2+1^2+2^2 so a(13)=1 and a(14)=1 and a(15)=1 and a(16)=2, 8=2^2+2^2 so a(17)=2 and a(18)=2, 9=3^2 so a(19)=3, etc...
CROSSREFS
KEYWORD
easy,nonn
AUTHOR
Ctibor O. Zizka, Mar 13 2010
STATUS
approved