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8, 24, 72, 216, 648, 1944, 5832, 17496, 52488, 157464, 472392, 1417176, 4251528, 12754584, 38263752, 114791256, 344373768, 1033121304, 3099363912, 9298091736, 27894275208, 83682825624, 251048476872, 753145430616, 2259436291848, 6778308875544, 20334926626632
(list; graph; refs; listen; history; internal format)
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OFFSET
| 0,1
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COMMENTS
| For n>=3, a(n-3) is equal to the number of functions f:{1,2,...,n}->{1,2,3} such that for fixed, different x_1, x_2, x_3 in {1,2,...,n} and fixed y_1, y_2, y_3 in {1,2,3} we have f(x_i)<>y_i, (i=1,2,3). - Milan R. Janjic (agnus(AT)blic.net), May 13 2007
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LINKS
| Vincenzo Librandi, Table of n, a(n) for n = 0..300
Index entries for sequences related to linear recurrences with constant coefficients
Milan Janjic, Enumerative Formulas for Some Functions on Finite Sets
Tanya Khovanova, Recursive Sequences
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MATHEMATICA
| 8*3^Range[0, 60] (* From Vladimir Joseph Stephan Orlovsky, June 09 2011 *)
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PROG
| (MAGMA) [8*3^n: n in [0..30]]; // Vincenzo Librandi, Jun 10 2011
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CROSSREFS
| Sequence in context: A200253 A199911 A083583 * A078158 A116486 A179609
Adjacent sequences: A005048 A005049 A005050 * A005052 A005053 A005054
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KEYWORD
| nonn
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AUTHOR
| N. J. A. Sloane (njas(AT)research.att.com).
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