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A081686
a(n) = 7^n - 6^n - 5^n - 4^n + 3*3^n.
1
1, 1, -1, 19, 467, 5611, 53459, 455659, 3648707, 28119691, 211372019, 1562038699, 11405181347, 82545287371, 593501306579, 4245828252139, 30255066944387, 214924122640651, 1522971386761139, 10770190567911979, 76039651374633827, 536127709619251531, 3775797660906839699, 26567026101757594219
OFFSET
0,4
COMMENTS
Binomial transform of A081685.
FORMULA
G.f.: -(1326*x^4-886*x^3+219*x^2-24*x+1)/((3*x-1)*(4*x-1)*(5*x-1)*(6*x-1)*(7*x-1)). [Colin Barker, Sep 07 2012]
From Elmo R. Oliveira, Sep 12 2024: (Start)
E.g.f.: exp(3*x)*(exp(4*x) - exp(3*x) - exp(2*x) - exp(x) + 3).
a(n) = 25*a(n-1) - 245*a(n-2) + 1175*a(n-3) - 2754*a(n-4) + 2520*a(n-5) for n > 4. (End)
CROSSREFS
Sequence in context: A285398 A201798 A284197 * A284163 A218477 A003700
KEYWORD
easy,sign
AUTHOR
Paul Barry, Mar 30 2003
EXTENSIONS
a(22)-a(23) from Elmo R. Oliveira, Sep 12 2024
STATUS
approved