OFFSET
0,2
COMMENTS
After 1, is this A208704?
LINKS
Colin Barker, Table of n, a(n) for n = 0..1000
Index entries for linear recurrences with constant coefficients, signature (7).
FORMULA
G.f.: (1-3*x)/(1-7*x).
a(n) = 7*a(n-1) for n>1.
a(n) = 4*7^(n-1) for n>0.
MATHEMATICA
CoefficientList[Series[(1 - 3 x)/(1 - 7 x), {x, 0, 21}], x] (* Michael De Vlieger, Mar 18 2016 *)
Join[{1}, NestList[7#&, 4, 20]] (* Harvey P. Dale, Dec 21 2019 *)
PROG
(PARI) Vec((1-3*x)/(1-7*x) + O(x^30))
CROSSREFS
KEYWORD
nonn,easy
AUTHOR
Colin Barker, Mar 17 2016
STATUS
approved