The number of permutations of the set {1,2,…,n} such that no three of 1, 2, 3, 4, appear consecutively can be given as
n!+24(n-2)!+24(n-3)!
n!-24(n-2)!+24(n-3)!
n!+24(n-2)!-24(n-3)!
n!-24(n-2)!-24(n-3)!
n!+24(n-1)!+24(n-2)!
I don’t know where to start or how , it would be very helpful if someone would provide me a hint
n!+24(n-2)!+24(n-3)!
n!-24(n-2)!+24(n-3)!
n!+24(n-2)!-24(n-3)!
n!-24(n-2)!-24(n-3)!
n!+24(n-1)!+24(n-2)!
I don’t know where to start or how , it would be very helpful if someone would provide me a hint
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