login
A198853
a(n) = 5*8^n - 1.
1
4, 39, 319, 2559, 20479, 163839, 1310719, 10485759, 83886079, 671088639, 5368709119, 42949672959, 343597383679, 2748779069439, 21990232555519, 175921860444159, 1407374883553279, 11258999068426239, 90071992547409919
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.: ( 4+3*x ) / ( (8*x-1)*(x-1) ). - R. J. Mathar, Oct 31 2011
PROG
(Magma) [5*8^n-1: n in [0..30]]
CROSSREFS
Sequence in context: A290559 A360740 A059945 * A093851 A224755 A241075
KEYWORD
nonn,easy
AUTHOR
Vincenzo Librandi, Oct 31 2011
STATUS
approved