A198855 a(n) = 7*8^n - 1.
6, 55, 447, 3583, 28671, 229375, 1835007, 14680063, 117440511, 939524095, 7516192767, 60129542143, 481036337151, 3848290697215, 30786325577727, 246290604621823, 1970324836974591, 15762598695796735, 126100789566373887
Offset: 0
Links
- Vincenzo Librandi, Table of n, a(n) for n = 0..1000
- Index entries for linear recurrences with constant coefficients, signature (9,-8).
Programs
-
Magma
[7*8^n-1: n in [0..30]]
Formula
a(n) = 8*a(n-1) + 7.
a(n) = 9*a(n-1) - 8*a(n-2), n > 1.
G.f.: ( 6+x ) / ( (8*x-1)*(x-1) ). - R. J. Mathar, Oct 31 2011