a(n) = n! * Sum_{k=0..floor(n/3)} (k+1)^(k-1) / (k! * (n-3*k)!).

A362523

a(n) = n! * Sum_{k=0..floor(n/3)} (k+1)^(k-1) / (k! * (n-3*k)!).

Terms

    a(0) =1a(1) =1a(2) =1a(3) =7a(4) =25a(5) =61a(6) =1201a(7) =7771a(8) =30577a(9) =1058905a(10) =9904321a(11) =53722351a(12) =2708688841a(13) =33126146197a(14) =228967340785

External references