OFFSET
1,2
LINKS
Vincenzo Librandi, Table of n, a(n) for n = 1..200
Index entries for linear recurrences with constant coefficients, signature (9,-8).
FORMULA
G.f.: 64*x^2/((1-x)*(1-8*x)).
a(n) = a(n-1) + 8^n.
a(n) = (8^(n+1) - 64)/7.
a(n) = 9*a(n-1) - 8*a(n-2).
a(n) = A052379(n) - 8. - Michel Marcus, Sep 25 2014
MATHEMATICA
RecurrenceTable[{a[1] == 0, a[n] == a[n-1] + 8^n}, a, {n, 30}] (* or *) CoefficientList[Series[64 x / ((1 - x) (1 - 8 x)), {x, 0, 30}], x]
LinearRecurrence[{9, -8}, {0, 64}, 30] (* Harvey P. Dale, May 01 2018 *)
PROG
(Magma) [0] cat [&+[8^k: k in [2..n]]: n in [2..30]]; /* or */ [(8^(n+1)-64)/7: n in [1..30]];
CROSSREFS
KEYWORD
nonn,easy
AUTHOR
Vincenzo Librandi, Sep 25 2014
STATUS
approved