OFFSET
1,5
LINKS
R. Zumkeller, Table of n, a(n) for n = 1..10000
FORMULA
a(n) = f(n,1) with f(m,p) = if p=m then 1 else (if p<m then f(m-1,(p+1)^2)+f(m,p+1) else 0).
EXAMPLE
a(10)=#{10,9+1}=2;
a(20)=#{20,19+1,18+2,17+3}=4;
a(30)=#{30,29+1,28+2,27+3,26+4,25+4+1}=6;
a(40)=#{40,39+1,38+2,37+3,36+4,35+4+1}=6;
a(50)=#{50,49+1,48+2,47+3,46+4,45+5,45+4+1,44+5+1}=8;
a(60)=#{60,59+1,58+2,57+3,56+4,55+5,55+4+1,54+6,54+5+1,53+6+1}=10.
CROSSREFS
KEYWORD
nonn
AUTHOR
Reinhard Zumkeller, Aug 10 2007
STATUS
approved