OFFSET
0,11
COMMENTS
a(n) = 0 for n == 9 (mod 10).
A generalization. For an even N >= 2, consider the determinant of circulant matrix of order N with entries in the first row (-1)^(j-1)K_j(n), j=1..N, where K_j(n) = Sum_{k>=0} (-1)^k*binomial(n, N*k+j-1). Then it is 0 for n == N-1 (mod N). This statement follows from an easily proved identity K_j(N*t + N - 1) = (-1)^t*K_(N - j + 1)(N*t + N - 1) and a known calculation formula for the determinant of circulant matrix [Wikipedia]. Besides, it is 0 for n=1..N-2. We also conjecture that every such sequence contains infinitely many blocks of N-1 negative and N-1 positive terms separated by 0's.
LINKS
Vladimir Shevelev, Combinatorial identities generated by difference analogs of hyperbolic and trigonometric functions of order n, arXiv:1706.01454 [math.CO], 2017.
Wikipedia, Circulant matrix
MAPLE
f:= n -> LinearAlgebra:-Determinant(Matrix(10, 10, shape=
Circulant[seq((-1)^j*add((-1)^k*binomial(n, 10*k+j),
k=0..(n-j)/10), j=0..9)])):
map(f, [$0..20]); # Robert Israel, Aug 08 2017
MATHEMATICA
ro[n_] := Table[(-1)^(j-1) Sum[(-1)^k Binomial[n, 10k+j-1], {k, 0, n/10}], {j, 1, 10}];
M[n_] := Table[RotateRight[ro[n], m], {m, 0, 9}];
a[n_] := Det[M[n]];
Table[a[n], {n, 0, 15}] (* Jean-François Alcover, Aug 10 2018 *)
CROSSREFS
KEYWORD
sign
AUTHOR
Vladimir Shevelev and Peter J. C. Moses, Aug 05 2017
STATUS
approved