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A137788
a(n) = 6^n - 5^n - 4^n - 3^n - 2^n.
1
-8, -18, -8, 318, 3352, 26142, 183112, 1216638, 7842232, 49591902, 309595432, 1915328958, 11771279512, 71987413662, 438579282952, 2664183937278, 16146410851192, 97676152243422, 590010212989672, 3559688008961598, 21455704973213272, 129219894479953182, 777738831202779592
OFFSET
1,1
FORMULA
From R. J. Mathar, Jun 15 2009: (Start)
G.f.: 2*x*(4 - 71*x + 444*x^2 - 1164*x^3 + 1080*x^4)/((6*x-1)*(4*x-1)*(3*x-1)*(2*x-1)*(5*x-1)).
a(n) = 20*a(n-1) - 155*a(n-2) + 580*a(n-3) - 1044*a(n-4) + 720*a(n-5). (End)
EXAMPLE
- 8*x - 18*x^2 - 8*x^3 + 318*x^4 + 3352*x^5 + 26142*x^6 + 183112*x^7 + ...
MAPLE
a:=proc (n) options operator, arrow: 6^n-5^n-4^n-3^n-2^n end proc: seq(a(n), n =1..20); # Emeric Deutsch, May 25 2008
MATHEMATICA
Array[6^#-5^#-4^#-3^#-2^# &, 10]
LinearRecurrence[{20, -155, 580, -1044, 720}, {-8, -18, -8, 318, 3352}, 30] (* Harvey P. Dale, Jan 23 2012 *)
PROG
(PARI) {a(n) = 6^n - 5^n - 4^n - 3^n - 2^n} /* Michael Somos, Jan 06 2012 */
CROSSREFS
Sequence in context: A107779 A018874 A163900 * A333828 A133202 A217424
KEYWORD
sign,easy
AUTHOR
EXTENSIONS
More terms from Alexander R. Povolotsky and Emeric Deutsch, May 01 2008
STATUS
approved