OFFSET
1,6
COMMENTS
FORMULA
Sum_{k=1..n} a(k) ~ Pi^10 * n^10 / 28217548800. - Vaclav Kotesovec, Sep 20 2024
MAPLE
b:= proc(n, k) option remember; `if`(k=0, `if`(n=0, 1, 0),
`if`(k=1, `if`(n=0, 0, numtheory[sigma](n)), (q->
add(b(j, q)*b(n-j, k-q), j=0..n))(iquo(k, 2))))
end:
a:= n-> b(n, 5):
seq(a(n), n=1..55); # Alois P. Heinz, Jul 26 2024
PROG
(Python)
from sympy import divisor_sigma
def A374978(n): return sum(divisor_sigma(j)*sum((5*divisor_sigma(i+1, 3)-(5+6*i)*divisor_sigma(i+1))*(5*divisor_sigma(n-j-i-1, 3)-(5+6*(n-j-i-2))*divisor_sigma(n-j-i-1)) for i in range(1, n-j-2)) for j in range(1, n))//144
CROSSREFS
KEYWORD
nonn
AUTHOR
Chai Wah Wu, Jul 26 2024
STATUS
approved