OFFSET
0,12
COMMENTS
LINKS
Milan Janjic, Binomial Coefficients and Enumeration of Restricted Words, Journal of Integer Sequences, 2016, Vol 19, #16.7.3
FORMULA
Number triangle T(n,k)=C(k+(n-k)/3,(n-k)/3)*(-1)^(n-k)*(2*cos(2*pi*(n-k)/3)+1)/3
EXAMPLE
Triangle begins
.1,
.0, 1,
.0, 0, 1,
.-1, 0, 0, 1,
.0, -2, 0, 0, 1,
.0, 0, -3, 0, 0, 1,
.1, 0, 0, -4, 0, 0, 1,
.0, 3, 0, 0, -5, 0, 0, 1,
.0, 0, 6, 0, 0, -6, 0, 0, 1,
.-1, 0, 0, 10, 0, 0, -7, 0, 0, 1,
.0, -4, 0, 0, 15, 0, 0, -8, 0, 0, 1
CROSSREFS
KEYWORD
AUTHOR
Paul Barry, Dec 15 2006
STATUS
approved