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A198855
a(n) = 7*8^n - 1.
2
6, 55, 447, 3583, 28671, 229375, 1835007, 14680063, 117440511, 939524095, 7516192767, 60129542143, 481036337151, 3848290697215, 30786325577727, 246290604621823, 1970324836974591, 15762598695796735, 126100789566373887
OFFSET
0,1
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
PROG
(Magma) [7*8^n-1: n in [0..30]]
CROSSREFS
Sequence in context: A097300 A295094 A295548 * A318592 A342388 A253475
KEYWORD
nonn,easy
AUTHOR
Vincenzo Librandi, Oct 31 2011
STATUS
approved