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A390032
Number of perfect overpartitions of 2*n-1: A390030(2*n-1).
0
2, 5, 5, 13, 5, 19, 5, 34, 13, 19, 5, 65, 5, 19, 21, 89, 5, 61, 5, 65, 21, 19, 5, 210, 13, 19, 32, 65, 5, 103, 5, 233, 21, 19, 21, 248, 5, 19, 21, 210, 5, 103, 5, 65, 70, 19, 5, 654, 13, 61, 21, 65, 5, 177, 21, 210, 21, 19, 5, 431, 5, 19, 70, 610, 21, 103, 5, 65, 21, 103
OFFSET
1,1
FORMULA
a(n) = A390030(2*n-1).
a(n) = Sum_{r=0..s} Sum_{v=r..s} binomial(v,r)*f_v(2*n), where s = A007814(2*n) and f_v(N) is the number of ordered factorizations of N having v copies of 2.
EXAMPLE
For n=2, the a(3)=5 perfect overpartitions of 3 are (1,1,1), (2,1), (2',1), (2,1'), (2',1').
CROSSREFS
KEYWORD
nonn
AUTHOR
Augustine O. Munagi, Oct 28 2025
STATUS
approved