This site is supported by donations to The OEIS Foundation.

 Hints (Greetings from The On-Line Encyclopedia of Integer Sequences!)
 A135690 Recursion based on J. Mortensen's programming page for Per Nørgård's "infinite series" music composition sequence technique. 0
 0, 1, -1, 2, -4, -2, -6, 0, -12, -8, -16, -4, -28, -20, -36, -12, -60, -44, -76, -28, -124, -92, -156, -60, -252, -188, -316, -124, -508, -380, -636, -252, -1020, -764, -1276, -508, -2044, -1532, -2556, -1020, -4092, -3068, -5116, -2044, -8188, -6140, -10236, -4092, -16380, -12284, -20476 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,4 COMMENTS Per Nørgård is a well-known classical music composer and his sequence method dates back to 1959. This sequence is new and was my third attempt to translate the web page into Mathematica programming. The composer Per Nørgård's name is also written in the OEIS as Per Noergaard. REFERENCES http : // www.pernoergaard.dk/eng/strukturer/uendelig/ukonstruktion05.html LINKS FORMULA pn(n) = If[Mod[n, 2] == 0, pn(n - 2) - (pn(n - 1) - pn(n - 2)), pn(n - 1) - (pn(n - 3) - pn(n - 4))]. Empirical G.f.: -x^2*(2*x-1)*(3*x^2+1) / ((x-1)*(2*x^4-1)). - Colin Barker, Jan 26 2013 MATHEMATICA pn[0] = 0; pn[1] = 1; pn[2] = -1; pn[3] = 2; pn[n_] := pn[n] = If[Mod[n, 2] == 0, pn[n - 2] - (pn[n - 1] - pn[ n - 2]), pn[n - 1] - (pn[n - 3] - pn[n - 4])] a = Table[pn[n], {n, 0, 50}] CROSSREFS Sequence in context: A198723 A198914 A207868 * A010241 A278526 A162630 Adjacent sequences:  A135687 A135688 A135689 * A135691 A135692 A135693 KEYWORD uned,sign AUTHOR Roger L. Bagula, Feb 19 2008 STATUS approved

Lookup | Welcome | Wiki | Register | Music | Plot 2 | Demos | Index | Browse | More | WebCam
Contribute new seq. or comment | Format | Style Sheet | Transforms | Superseeker | Recent
The OEIS Community | Maintained by The OEIS Foundation Inc.

Last modified July 23 11:44 EDT 2019. Contains 325254 sequences. (Running on oeis4.)