OFFSET
1,3
COMMENTS
Case k=5,i=5 of Gordon/Goellnitz/Andrews Theorem.
REFERENCES
G. E. Andrews, The Theory of Partitions, Addison-Wesley, 1976, p. 114.
FORMULA
a(n) ~ exp(Pi*sqrt(2*n/5)) * cos(Pi/20) / (10^(3/4) * n^(3/4)). - Vaclav Kotesovec, May 10 2018
MATHEMATICA
nmax = 60; Rest[CoefficientList[Series[Product[(1 - x^(4*k - 2))*(1 - x^(20*k))*(1 - x^(20*k+9-20))*(1 - x^(20*k- 9))/(1 - x^k), {k, 1, nmax}], {x, 0, nmax}], x]] (* Vaclav Kotesovec, May 10 2018 *)
CROSSREFS
KEYWORD
nonn,easy
AUTHOR
EXTENSIONS
Name corrected by Vaclav Kotesovec, May 09 2018
STATUS
approved