A383138 a(n) = Sum_{k=0..n} k^4 * 2^(n-k) * binomial(n,k).
0, 1, 20, 189, 1320, 7785, 41148, 201285, 929232, 4100625, 17452260, 72098829, 290521080, 1146082041, 4439303820, 16923738645, 63619864992, 236206924065, 867305334708, 3152957079645, 11359168737480, 40589657212041, 143957705302620, 507079568653029
Offset: 0
Programs
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PARI
a(n) = 3^(n-4)*n*(-6+20*n+12*n^2+n^3);
Formula
a(n) = 3^(n-4) * n * (-6 + 20*n + 12*n^2 + n^3).