A137790 a(n) = 8^n-7^n-6^n-5^n-4^n-3^n-2^n.

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

Table of n, a(n) for n=5..22.

Index entries for linear recurrences with constant coefficients, signature (35,-511,4025,-18424,48860,-69264,40320).

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

Adjacent sequences: A137787 A137788 A137789 * A137791 A137792 A137793

Keyword

nonn,easy

Author

Vladimir Joseph Stephan Orlovsky, Apr 28 2008

Extensions

More terms from Colin Barker, Nov 05 2012

Offset corrected by Tanya Khovanova, Jul 05 2021

Status

approved