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A198692
a(n) = 11*7^n-1.
1
10, 76, 538, 3772, 26410, 184876, 1294138, 9058972, 63412810, 443889676, 3107227738, 21750594172, 152254159210, 1065779114476, 7460453801338, 52223176609372, 365562236265610, 2558935653859276, 17912549577014938
OFFSET
0,1
FORMULA
a(n) = 7*a(n-1)+6. a(n) = 8*a(n-1)-7*a(n-2), n>1.
G.f.: ( 10-4*x ) / ( (7*x-1)*(x-1) ). - R. J. Mathar, Oct 30 2011
MATHEMATICA
11 (7^Range[0, 30]) - 1 (* Wesley Ivan Hurt, Jan 21 2017 *)
PROG
(Magma) [11*7^n-1: n in [0..30]]
CROSSREFS
KEYWORD
nonn,easy
AUTHOR
Vincenzo Librandi, Oct 29 2011
STATUS
approved