OFFSET
0,4
LINKS
Vaclav Kotesovec, Table of n, a(n) for n = 0..1000
FORMULA
a(n) ~ (1+sqrt(2) + (-1)^n*(1-sqrt(2))) * 2^(n/2 - 1).
MATHEMATICA
nmax = 60; 2^Range[0, nmax] - CoefficientList[Series[Product[(1 - x^k)/(1 - 2*x^k), {k, 1, nmax}], {x, 0, nmax}], x]
CROSSREFS
KEYWORD
nonn
AUTHOR
Vaclav Kotesovec, Nov 21 2015
STATUS
approved