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.

A141125 Hankel transform of a transform of Fibonacci numbers.

Original entry on oeis.org

1, 4, -4, -16, 16, 64, -64, -256, 256, 1024, -1024, -4096, 4096, 16384, -16384, -65536, 65536, 262144, -262144, -1048576, 1048576, 4194304, -4194304, -16777216, 16777216, 67108864, -67108864, -268435456, 268435456, 1073741824, -1073741824, -4294967296, 4294967296
Offset: 0

Views

Author

Paul Barry, Jun 05 2008

Keywords

Comments

Hankel transform of A100095(n+1).

Crossrefs

Programs

  • Mathematica
    LinearRecurrence[{0,-4},{1,4},33] (* or *) CoefficientList[Series[(1+4x)/(1+4x^2),{x,0,32}],x] (* James C. McMahon, Jul 17 2025 *)

Formula

G.f.: (1+4x)/(1+4x^2).
a(n) = 2^n*(cos(Pi*n/2)+2*sin(Pi*n/2)).
a(n+3) = a(n+2)*a(n+1)/a(n). - Reinhard Zumkeller, Mar 04 2011
E.g.f.: cos(2*x) + 2*sin(2*x). - Stefano Spezia, Jul 18 2025

Extensions

More terms from James C. McMahon, Jul 18 2025