A024078 a(n) = 7^n - n^3.
1, 6, 41, 316, 2337, 16682, 117433, 823200, 5764289, 40352878, 282474249, 1977325412, 13841285473, 96889008210, 678223070105, 4747561506568, 33232930565505, 232630513982294, 1628413597904617, 11398895185366284, 79792266297604001, 558545864083274746
Offset: 0
Links
- Vincenzo Librandi, Table of n, a(n) for n = 0..500
- Index entries for linear recurrences with constant coefficients, signature (11,-34,46,-29,7).
Programs
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Magma
[7^n-n^3: n in [0..25]]; // Vincenzo Librandi, Jul 03 2011
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PARI
Vec((1 + x)*(1 - 6*x + 15*x^2 + 8*x^3) / ((1 - x)^4*(1 - 7*x)) + O(x^30)) \\ Colin Barker, Oct 05 2018
Formula
From Colin Barker, Oct 05 2018: (Start)
G.f.: (1 + x)*(1 - 6*x + 15*x^2 + 8*x^3) / ((1 - x)^4*(1 - 7*x)).
a(n) = 11*a(n-1) - 34*a(n-2) + 46*a(n-3) - 29*a(n-4) + 7*a(n-5) for n>4.
(End)