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A190069 Number of arrangements of n+1 nonzero numbers x(i) in -7..7 with the sum of div(x(i),x(i+1)), where div(a,b)=a/b produces the integer quotient implying a nonnegative remainder, equal to zero.

%I A190069 #7 Jul 22 2025 12:00:33
%S A190069 42,366,4150,48491,599181,7737762,101530262,1333341624,17643516841,
%T A190069 235162515839,3146321736755,42232649776342,568807797004946,
%U A190069 7683091138249061,104022021281511319,1411291383524511348
%N A190069 Number of arrangements of n+1 nonzero numbers x(i) in -7..7 with the sum of div(x(i),x(i+1)), where div(a,b)=a/b produces the integer quotient implying a nonnegative remainder, equal to zero.
%C A190069 Column 7 of A190071
%H A190069 R. H. Hardin, <a href="/A190069/b190069.txt">Table of n, a(n) for n = 1..81</a>
%e A190069 Some solutions for n=4
%e A190069 ..5....3...-4...-5....7....3....1....1....5...-3....3....1...-4....2....4....5
%e A190069 .-5....5...-6...-5....3...-2...-3....2...-1...-2...-3...-5...-2...-3....6...-1
%e A190069 .-5...-3...-7...-7...-2...-7...-3....6....3....1....6....3...-7....2...-5...-1
%e A190069 ..7...-2....4....7....2...-5...-4....6....6....2....4...-7....6....1...-3...-7
%e A190069 ..5....4....5...-6...-3....4....3...-5....1....7....4...-5...-5...-4....5...-3
%K A190069 nonn
%O A190069 1,1
%A A190069 _R. H. Hardin_ May 04 2011