OFFSET
0,2
LINKS
Index entries for linear recurrences with constant coefficients, signature (-7,-21,-35,-35,-21,-7,1).
FORMULA
a(n) = -7*a(n-1) - 21*a(n-2) - 35*a(n-3) - 35*a(n-4) - 21*a(n-5) - 7*a(n-6) + a(n-7).
a(n) = (-1)^n * Sum_{k=0..floor(n/7)} (-2)^k * binomial(n+6,7*k+6).
PROG
(PARI) my(N=40, x='x+O('x^N)); Vec(1/((1+x)^7-2*x^7))
CROSSREFS
KEYWORD
sign,easy
AUTHOR
Seiichi Manyama, Aug 05 2024
STATUS
approved