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 A225220 Number of lattice paths without interior points from {n}^4 to {0}^4 using steps that decrement one component by 1. 2

%I

%S 1,24,1944,132000,8059800,471369024,27141228576,1557898303104,

%T 89658680843160,5186780199744000,301901643282754944,

%U 17682835350047107968,1041936263500353390624,61736371470508652400000,3676501723843796568912000,219941299213693627194432000

%N Number of lattice paths without interior points from {n}^4 to {0}^4 using steps that decrement one component by 1.

%C An interior point p = (p_1, ..., p_4) has 4 components with 0<p_i<n for 1<=i<=4.

%H Alois P. Heinz, <a href="/A225220/b225220.txt">Table of n, a(n) for n = 0..100</a>

%p b:= proc(n, l) b(n, l):= `if`(l[4]=0, 1, `if`(l[1]>0 and l[4]<n, 0,

%p add(`if`(l[i]=0, 0, b(n, sort(subsop(i=l[i]-1, l)))), i=1..4)))

%p end:

%p a:= n-> b(n, [n\$4]):

%p seq(a(n), n=0..20);

%Y Column k=4 of A225094.

%K nonn

%O 0,2

%A _Alois P. Heinz_, May 02 2013

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Last modified September 17 11:03 EDT 2019. Contains 327129 sequences. (Running on oeis4.)