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A298594
Triangle read by rows: T(n,k) = number of parking functions a of length n such that a(1) = k and if we replace a(1) = k with k+1 we don't get a parking function.
3
1, 1, 1, 3, 2, 3, 16, 9, 9, 16, 125, 64, 54, 64, 125, 1296, 625, 480, 480, 625, 1296, 16807, 7776, 5625, 5120, 5625, 7776, 16807, 262144, 117649, 81648, 70000, 70000, 81648, 117649, 262144, 4782969, 2097152, 1411788, 1161216, 1093750, 1161216, 1411788, 2097152, 4782969
OFFSET
1,4
FORMULA
T(n,k) = binomial(n-1, k-1)*k^(k-2)*(n+1-k)^(n-1-k).
T(n,k) = A298592(n,k) - A298592(n,k+1).
T(n,k) = (A298593(n,k) - A298593(n,k+1))/n.
T(n,k) = A298597(n,k)/n.
T(n,1) = A000272(n+2).
T(n,n) = A000272(n+2).
T(n,k) = T(n,n-k).
EXAMPLE
Triangle begins:
1;
1, 1;
3, 2, 3;
16, 9, 9, 16;
125, 64, 54, 64, 125;
1296, 625, 480, 480, 625, 1296;
16807, 7776, 5625, 5120, 5625, 7776, 16807;
262144, 117649, 81648, 70000, 70000, 81648, 117649, 262144;
...
MATHEMATICA
Table[Binomial[n - 1, k - 1] k^(k - 2)*(n + 1 - k)^(n - 1 - k), {n, 9}, {k, n}] // Flatten (* Michael De Vlieger, Jan 22 2018 *)
CROSSREFS
KEYWORD
easy,nonn,tabl
AUTHOR
Rui Duarte, Jan 22 2018
STATUS
approved