cp's OEIS Frontend

A188358 T(n,k)=Number of arrangements of n+1 numbers x(i) in -k..k with the sum of x(i)*x(i+1) equal to zero.

%I A188358 #7 Jul 22 2025 11:10:03
%S A188358 5,9,15,13,45,29,17,91,117,91,21,153,257,565,197,25,231,497,1775,1953,
%T A188358 627,29,325,749,4201,7369,9153,1477,33,435,1205,8051,22229,49747,
%U A188358 37269,4671,37,561,1569,14477,45801,181449,262925,173409,11693,41,703,2161
%N A188358 T(n,k)=Number of arrangements of n+1 numbers x(i) in -k..k with the sum of x(i)*x(i+1) equal to zero.
%C A188358 Table starts
%C A188358 .....5.......9.......13........17.........21..........25..........29
%C A188358 ....15......45.......91.......153........231.........325.........435
%C A188358 ....29.....117......257.......497........749........1205........1569
%C A188358 ....91.....565.....1775......4201.......8051.......14477.......22583
%C A188358 ...197....1953.....7369.....22229......45801......100885......163745
%C A188358 ...627....9153....49747....181449.....480363.....1171345.....2295051
%C A188358 ..1477...37269...262925...1264985....3882729....11535493....25217201
%C A188358 ..4671..173409..1763151..10396729...40629247...136061137...355442823
%C A188358 .11693..766869.10536621..81850801..383541193..1540834589..4602176797
%C A188358 .36487.3589357.70819767.684867741.4033546763.18592832393.65556183495
%H A188358 R. H. Hardin, <a href="/A188358/b188358.txt">Table of n, a(n) for n = 1..178</a>
%e A188358 Some solutions for n=6 k=4
%e A188358 .-4...-1...-4....0....3....0...-1....0...-4...-1...-1...-1...-2...-1....1...-3
%e A188358 ..0...-2...-3...-2...-4...-4...-3...-4....0...-1...-2...-3...-2....0...-2...-1
%e A188358 .-4....2....3....1....3....4...-3...-1....4....0....1....1...-2....4....1....1
%e A188358 ..4...-1...-1....1....3....4....0...-2....0....0...-3...-4....1...-4...-4....2
%e A188358 ..4....2....2....1....1....0....1....3...-2...-3...-1...-1...-2...-4....3...-3
%e A188358 ..3....1...-2....0...-4....1...-3...-2....0...-1....0....2....1...-4....4...-1
%e A188358 .-4....4...-3...-1...-4....0....3...-3...-4....4....3....1...-2....4....2....1
%Y A188358 Row 1 is A016813
%Y A188358 Row 2 is A014634
%K A188358 nonn,tabl
%O A188358 1,1
%A A188358 _R. H. Hardin_ Mar 28 2011