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A199555
7*8^n+1.
2
8, 57, 449, 3585, 28673, 229377, 1835009, 14680065, 117440513, 939524097, 7516192769, 60129542145, 481036337153, 3848290697217, 30786325577729, 246290604621825, 1970324836974593, 15762598695796737, 126100789566373889
OFFSET
0,1
FORMULA
a(n) = 8*a(n-1)-7.
a(n) = 9*a(n-1)-8*a(n-2).
G.f.: (8-15*x)/((1-x)*(1-8*x)).
PROG
(Magma) [7*8^n+1: n in [0..30]];
CROSSREFS
Sequence in context: A343352 A307642 A338676 * A241594 A241595 A208596
KEYWORD
nonn,easy
AUTHOR
Vincenzo Librandi, Nov 08 2011
STATUS
approved