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Search: id:A001631
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| A001631 |
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Tetranacci numbers: a(n) = a(n-1) + a(n-2) + a(n-3) +a(n-4).
(Formerly M1081 N0410)
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+0
3
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| 0, 0, 1, 0, 1, 2, 4, 7, 14, 27, 52, 100, 193, 372, 717, 1382, 2664, 5135, 9898, 19079, 36776, 70888, 136641, 263384, 507689, 978602, 1886316, 3635991, 7008598, 13509507, 26040412, 50194508, 96753025, 186497452, 359485397, 692930382
(list; graph; listen)
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OFFSET
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0,6
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REFERENCES
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W. C. Lynch, The t-Fibonacci numbers and polyphase sorting, Fib. Quart., 8 (1970), pp. 6ff.
N. J. A. Sloane, A Handbook of Integer Sequences, Academic Press, 1973 (includes this sequence).
N. J. A. Sloane and Simon Plouffe, The Encyclopedia of Integer Sequences, Academic Press, 1995 (includes this sequence).
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LINKS
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S. Plouffe, Approximations de S\'{e}ries G\'{e}n\'{e}ratrices et Quelques Conjectures, Dissertation, Universit\'{e} du Qu\'{e}bec \`{a} Montr\'{e}al, 1992.
S. Plouffe, 1031 Generating Functions and Conjectures, Universit\'{e} du Qu\'{e}bec \`{a} Montr\'{e}al, 1992.
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MAPLE
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A001631:=(-1+z)/(-1+z+z**2+z**3+z**4); [Conjectured by S. Plouffe in his 1992 dissertation.]
(Maple) a := n -> (Matrix([[0, -1, 2, -1]]). Matrix(4, (i, j)-> if (i=j-1) or j=1 then 1 else 0 fi)^n)[1, 1] ; seq (a(n), n=0..35); [From Alois P. Heinz (heinz(AT)hs-heilbronn.de), Aug 01 2008]
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CROSSREFS
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First differences of A000078.
Sequence in context: A005594 A123196 A079968 this_sequence A108758 A018085 A167751
Adjacent sequences: A001628 A001629 A001630 this_sequence A001632 A001633 A001634
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KEYWORD
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nonn,easy
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AUTHOR
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N. J. A. Sloane (njas(AT)research.att.com).
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EXTENSIONS
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More terms from Larry Reeves (larryr(AT)acm.org), Jul 31 2000
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