a(0) = 0, a(1) = 1, and for n >= 2, a(n) = (n-1) * a(n-2) + (n-2) * a(n-1).

A153229

a(0) = 0, a(1) = 1, and for n >= 2, a(n) = (n-1) * a(n-2) + (n-2) * a(n-1).

Terms

    a(0) =0a(1) =1a(2) =0a(3) =2a(4) =4a(5) =20a(6) =100a(7) =620a(8) =4420a(9) =35900a(10) =326980a(11) =3301820a(12) =36614980a(13) =442386620a(14) =5784634180a(15) =81393657020

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