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A016135
Expansion of 1/((1-2*x)*(1-11*x)).
6
1, 13, 147, 1625, 17891, 196833, 2165227, 23817625, 261994131, 2881935953, 31701296507, 348714263625, 3835856903971, 42194425951873, 464138685486987, 5105525540389625, 56160780944351411, 617768590387996593, 6795454494268224667, 74749999436950995625
OFFSET
0,2
FORMULA
a(n) = (11^(n+1) - 2^(n+1))/9. - Zerinvary Lajos, Jun 05 2009
a(n) = 13*a(n-1) - 22*a(n-2). - Vincenzo Librandi, Jun 02 2011
MATHEMATICA
LinearRecurrence[{13, -22}, {1, 13}, 30] (* or *) CoefficientList[Series[ 1/((1-2x)*(1-11x)), {x, 0, 30}], x] (* Harvey P. Dale, Oct 15 2011 *)
PROG
(Sage) [(11^(n+1) - 2^(n+1))/9 for n in range(0, 20)] # Zerinvary Lajos, Jun 05 2009
(PARI) a(n)=(11^n++-2^n)/9 \\ Charles R Greathouse IV, Mar 26 2012
CROSSREFS
Cf. A139740.
Sequence in context: A051524 A110748 A211072 * A332691 A210165 A132156
KEYWORD
nonn,easy
EXTENSIONS
Incorrect comment removed by Charles R Greathouse IV, Mar 26 2012
STATUS
approved