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A131292
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a(2n+1)=3a(2n)-3a(2n-1)+2a(2n-2), a(2n+2)=3a(2n+1)-3a(2n), a(0)=a(1)=a(2)=1.
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3
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1, 1, 1, 2, 3, 5, 6, 9, 9, 12, 9, 9, 0, -9, -27, -54, -81, -135, -162, -243, -243, -324, -243, -243, 0, 243, 729, 1458, 2187, 3645, 4374, 6561, 6561, 8748, 6561, 6561, 0, -6561, -19683, -39366, -59049, -98415, -118098, -177147, -177147, -236196, -177147, -177147, 0, 177147, 531441, 1062882, 1594323
(list; graph; refs; listen; history; internal format)
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OFFSET
| 0,4
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COMMENTS
| Sequence is identical to its third differences in absolute value.
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FORMULA
| G.f.: (2*x^3-x^2-x+1)*(1+x)^2/(1-3*x^2+3*x^4). [From R. J. Mathar (mathar(AT)strw.leidenuniv.nl), Jul 17 2009]
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MAPLE
| A131292 := proc(n) option remember ; if n <= 2 then 1; elif n mod 2 = 1 then 3*(A131292(n-1)-A131292(n-2))+2*A131292(n-3) ; else 3*(A131292(n-1)-A131292(n-2)) ; fi ; end: seq(A131292(n), n=0..80) ; - R. J. Mathar (mathar(AT)strw.leidenuniv.nl), Oct 18 2007
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CROSSREFS
| Cf. A131665 (0, 0, 1, 3, 6, 11).
Cf. A057083 (bisection). [From R. J. Mathar (mathar(AT)strw.leidenuniv.nl), Jul 17 2009]
Sequence in context: A075389 A053784 A036697 * A069880 A069861 A047449
Adjacent sequences: A131289 A131290 A131291 * A131293 A131294 A131295
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KEYWORD
| sign,easy
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AUTHOR
| Paul Curtz (bpcrtz(AT)free.fr), Sep 29 2007
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EXTENSIONS
| More terms from R. J. Mathar (mathar(AT)strw.leidenuniv.nl), Oct 18 2007
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