OFFSET
1,3
COMMENTS
a(n) is also the number of partitions of n with no part equal to 2 or 4. [From Shanzhen Gao, Oct 28 2010]
FORMULA
G.f.: (1+x)*(1+x^2)/Product_{k>=3} (1-x^k). - Vladeta Jovovic, Aug 13 2006
Given by p(n)-p(n-2)-p(n-4)+p(n-6) where p(n)=A000041(n). - Shanzhen Gao, Oct 28 2010
a(n) ~ exp(Pi*sqrt(2*n/3)) * Pi^2 / (3^(3/2) * n^2). - Vaclav Kotesovec, Jun 02 2018
EXAMPLE
a(8)=#{8,7+1,6+2,5+3,5+2+1,4+4,4+3+1,3+3+2}=8;
a(9)=#{9,8+1,7+2,6+3,6+2+1,5+4,5+3+1,4+4+1,4+3+2,3+3+3,3+3+2+1}=11.
CROSSREFS
KEYWORD
nonn
AUTHOR
Reinhard Zumkeller, Aug 11 2006
STATUS
approved