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A198690
a(n) = 9*7^n-1.
1
8, 62, 440, 3086, 21608, 151262, 1058840, 7411886, 51883208, 363182462, 2542277240, 17795940686, 124571584808, 872001093662, 6104007655640, 42728053589486, 299096375126408, 2093674625884862, 14655722381194040, 102590056668358286, 718130396678508008, 5026912776749556062
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.: ( 8-2*x ) / ( (7*x-1)*(x-1) ). - R. J. Mathar, Oct 30 2011
MATHEMATICA
9*7^Range[0, 30]-1 (* or *) LinearRecurrence[{8, -7}, {8, 62}, 30] (* Harvey P. Dale, Apr 22 2019 *)
PROG
(Magma) [9*7^n-1: n in [0..30]];
CROSSREFS
KEYWORD
nonn,easy
AUTHOR
Vincenzo Librandi, Oct 29 2011
STATUS
approved