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A083225
a(n) = (7*8^n + (-8)^n)/8.
3
1, 6, 64, 384, 4096, 24576, 262144, 1572864, 16777216, 100663296, 1073741824, 6442450944, 68719476736, 412316860416, 4398046511104, 26388279066624, 281474976710656, 1688849860263936, 18014398509481984, 108086391056891904
OFFSET
0,2
FORMULA
a(n) = (7*8^n + (-8)^n)/8.
G.f.: (1+6*x)/((1+8*x)*(1-8*x)).
E.g.f.: (7*exp(8*x) + exp(-8*x))/8.
a(n) = 64*a(n-2); a(0)=1, a(1)=6. - Harvey P. Dale, Apr 22 2012
MATHEMATICA
Table[(7*8^n+(-8)^n)/8, {n, 0, 20}] (* or *) LinearRecurrence[{0, 64}, {1, 6}, 20] (* Harvey P. Dale, Apr 22 2012 *)
PROG
(Magma) [(7*8^n+(-8)^n)/8: n in [0..25]]; // Vincenzo Librandi, Jun 29 2011
(PARI) a(n)= (7*8^n+(-8)^n)/8 \\ Charles R Greathouse IV, Jun 29 2011
CROSSREFS
Sequence in context: A218383 A222596 A067447 * A320528 A237357 A230282
KEYWORD
easy,nonn
AUTHOR
Paul Barry, Apr 23 2003
STATUS
approved