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A064838
a(n) = A064837(n)/2.
2
0, 1, 9, 57, 210, 585, 1355, 2769, 5156, 8945, 14669, 22985, 34678, 50681, 72079, 100129, 136264, 182113, 239505, 310489, 397338, 502569, 628947, 779505, 957548, 1166673, 1410773, 1694057, 2021054, 2396633, 2826007, 3314753
OFFSET
0,3
FORMULA
From Chai Wah Wu, Aug 01 2020: (Start)
a(n) = 5*a(n-1) - 9*a(n-2) + 5*a(n-3) + 5*a(n-4) - 9*a(n-5) + 5*a(n-6) - a(n-7) for n > 6.
G.f.: x*(-x^5 - 2*x^4 + x^3 + 21*x^2 + 4*x + 1)/((x - 1)^6*(x + 1)). (End)
MATHEMATICA
LinearRecurrence[{5, -9, 5, 5, -9, 5, -1}, {0, 1, 9, 57, 210, 585, 1355}, 40] (* Harvey P. Dale, Nov 18 2022 *)
PROG
(PARI) { for (n=0, 500, a=(6*n^4 + 30*n^3 - 20*n^2 + 14)*n/30 + n%2; write("b064838.txt", n, " ", a/2) ) } \\ Harry J. Smith, Sep 28 2009
CROSSREFS
Sequence in context: A086888 A231315 A338080 * A027210 A192054 A045720
KEYWORD
nonn,easy
AUTHOR
N. J. A. Sloane, Oct 25 2001
EXTENSIONS
Offset changed from 1 to 0 by Harry J. Smith, Sep 28 2009
STATUS
approved