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A137790
a(n) = 8^n-7^n-6^n-5^n-4^n-3^n-2^n.
0
3761, 77325, 896849, 8869821, 81550961, 719926125, 6196609169, 52439953821, 438516694961, 3635082523725, 29935019892689, 245264010263421, 2001462391659761, 16280541150478125, 132087583623451409, 1069376609438070621, 8642407976463949361, 69743131733050637325
OFFSET
5,1
COMMENTS
The sequence starts at n=5 as for n<5 the result is negative. - Tanya Khovanova, Jul 05 2021
LINKS
FORMULA
G.f.: x^5*(23345280*x^6 -29177136*x^5 +12543396*x^4 -1855156*x^3 -112345*x^2 +54310*x -3761)/((2*x -1)*(3*x -1)*(4*x -1)*(5*x -1)*(6*x -1)*(7*x -1)*(8*x -1)). - Colin Barker, Nov 05 2012
EXAMPLE
a(5) = 8^5 - 7^5 - 6^5 - 5^5 - 4^5 - 3^5 - 2^5 = 3761. - Tanya Khovanova, Jul 05 2021
MATHEMATICA
Array[8^#-7^#-6^#-5^#-4^#-3^#-2^# &, 10, 0]
LinearRecurrence[{35, -511, 4025, -18424, 48860, -69264, 40320}, {3761, 77325, 896849, 8869821, 81550961, 719926125, 6196609169}, 20] (* Harvey P. Dale, Sep 04 2017 *)
PROG
(Python)
def a(n): return 8**n - 7**n - 6**n - 5**n - 4**n - 3**n - 2**n
print([a(n) for n in range(5, 23)]) # Michael S. Branicky, Jul 05 2021
CROSSREFS
Sequence in context: A133969 A133970 A252564 * A300796 A338545 A284079
KEYWORD
nonn,easy
AUTHOR
EXTENSIONS
More terms from Colin Barker, Nov 05 2012
Offset corrected by Tanya Khovanova, Jul 05 2021
STATUS
approved