cp's OEIS Frontend

This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.

Showing 1-2 of 2 results.

A140343 a(n)=4a(n-1)-7a(n-2)+6a(n-3)-3a(n-4), n>4.

Original entry on oeis.org

0, 0, 0, 0, 1, 4, 9, 14, 14, 0, -41, -122, -243, -364, -364, 0, 1093, 3280, 6561, 9842, 9842, 0, -29525, -88574, -177147, -265720, -265720, 0, 797161, 2391484, 4782969, 7174454, 7174454, 0, -21523361, -64570082, -129140163, -193710244, -193710244, 0, 581130733
Offset: 0

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Author

Paul Curtz, May 29 2008

Keywords

Comments

This is the main sequence representing the degenerate case of sequences which equal their sixth differences, where, besides the generic a(n)=6a(n-1)-15a(n-2)+20a(n-3)-15a(n-4)+6a(n-5), cf. A135356, there is also a shorter recurrence. Another sequence of this kind is A134581.

Crossrefs

Cf. A135356.

Programs

  • Mathematica
    Join[{0},LinearRecurrence[{4,-7,6,-3},{0,0,0,1},40]] (* Harvey P. Dale, Mar 11 2015 *)

Formula

O.g.f.: x^4/((x^2-x+1)(3x^2-3x+1)). - R. J. Mathar, Jul 10 2008

Extensions

Edited and corrected by R. J. Mathar, Jul 10 2008

A106233 An inverse Catalan transform of A003462.

Original entry on oeis.org

0, 1, 3, 5, 5, 0, -14, -41, -81, -121, -121, 0, 364, 1093, 2187, 3281, 3281, 0, -9842, -29525, -59049, -88573, -88573, 0, 265720, 797161, 1594323, 2391485, 2391485, 0, -7174454, -21523361, -43046721, -64570081, -64570081, 0, 193710244, 581130733, 1162261467
Offset: 0

Views

Author

Paul Barry, Apr 26 2005

Keywords

Comments

The g.f. is obtained from that of A003462 through the mapping g(x)->g(x(1-x)). A003462 may be retrieved through the mapping g(x)->g(xc(x)), where c(x) is the g.f. of A000108. Binomial transform of x(1+x)/(1+x^2+x^4).
The sequence is identical to its sixth differences. See A140344. - Paul Curtz, Nov 09 2012

Examples

			From _Paul Curtz_, Nov 09 2012: (Start)
The sequence and its higher-order differences (periodic after 6 rows):
   0,  1,  3,  5,  5,   0, -14, ...
   1,  2,  2,  0, -5, -14, -27, ...
   1,  0, -2, -5, -9, -13, -13, ...
  -1, -2, -3, -4, -4,   0,  13, ...   = -A134581(n+1)
  -1, -1, -1,  0,  4,  13,  27, ...
   0,  0,  1,  4,  9,  14,  14, ...   = A140343(n+2)
   0,  1,  3,  5,  5,   0, -14, ...
(End)
		

Crossrefs

Cf. A103368.

Programs

  • Magma
    I:=[0,1,3,5]; [n le 4 select I[n] else 4*Self(n-1)-7*Self(n-2)+ 6*Self(n-3)-3*Self(n-4): n in [1..40]]; // Vincenzo Librandi, Dec 24 2018
  • Mathematica
    LinearRecurrence[{4, -7, 6, -3}, {0, 1, 3, 5}, 35] (* Vincenzo Librandi, Dec 24 2018 *)

Formula

G.f.: x(1-x)/((1-x+x^2)*(1-3*x+3*x^2));
a(n) = Sum_{k=0..floor(n/2)} C(n-k, k)*(-1)^k*(3^(n-k)-1)/2.
a(n) = Sum_{k=0..n} A109466(n,k)*A003462(k). - Philippe Deléham, Oct 30 2008
a(n) = (1/2)*[A057083(n) - [1,1,0,0,-1,-1]6 ]. - _Ralf Stephan, Nov 15 2010
a(n) = 4*a(n-1) - 7*a(n-2) + 6*a(n-3) - 3*a(n-4) = A140343(n+2) - A140343(n+1). - Paul Curtz, Nov 09 2012
a(n) is the binomial transform of the sequence 0, 1, 1, -1, -1, 0, ... = A103368(n+5). - Paul Curtz, Nov 09 2012
Showing 1-2 of 2 results.