A368789 a(n) = (n+1)^2 * (n!)^3 * Sum_{k=1..n} 1/((k+1)^2 * (k!)^3).
0, 1, 19, 913, 91301, 16434181, 4831649215, 2164578848321, 1402647093712009, 1262382384340808101, 1527482685052377802211, 2419532573122966438702225, 4906812058293375937688112301, 12502557124531521889229310142949
Offset: 0
Keywords
Programs
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PARI
a(n) = (n+1)^2*n!^3*sum(k=1, n, 1/((k+1)^2*k!^3));
Formula
a(0) = 0; a(n) = (n+1)^2 * n * a(n-1) + 1.
a(n) = A368776(n) - (n+1)^2 * (n!)^3.