

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
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OFFSET

1,4


COMMENTS

Per Nørgård is a wellknown 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

Table of n, a(n) for n=1..51.


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*x1)*(3*x^2+1) / ((x1)*(2*x^41)).  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



