

A092533


G.f.: (1+x^8)/((1x)*(1x^4)).


2



1, 1, 1, 1, 2, 2, 2, 2, 4, 4, 4, 4, 6, 6, 6, 6, 8, 8, 8, 8, 10, 10, 10, 10, 12, 12, 12, 12, 14, 14, 14, 14, 16, 16, 16, 16, 18, 18, 18, 18, 20, 20, 20, 20, 22, 22, 22, 22, 24, 24, 24, 24, 26, 26, 26, 26, 28, 28, 28, 28, 30, 30, 30, 30, 32, 32, 32, 32, 34, 34, 34, 34, 36, 36, 36, 36, 38, 38
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OFFSET

0,5


LINKS

Vincenzo Librandi, Table of n, a(n) for n = 0..1000
G. Nebe, E. M. Rains and N. J. A. Sloane, SelfDual Codes and Invariant Theory, Springer, Berlin, 2006.
Index entries for Molien series
Index entries for linear recurrences with constant coefficients, signature (1,0,0,1,1).


FORMULA

a(n) = 1 for n<4, a(n) = 2*floor(n/4) for n>=4.  Ralf Stephan, Apr 29 2014


MATHEMATICA

CoefficientList[Series[(1+x^8)/((1x)(1x^4)), {x, 0, 100}], x] (* or *) Join[{1, 1, 1, 1}, LinearRecurrence[{1, 0, 0, 1, 1}, {2, 2, 2, 2, 4}, 80]] (* Harvey P. Dale, Jul 25 2014 *)


PROG

(MAGMA) I:=[1, 1, 1, 1, 2, 2, 2, 2, 4]; [n le 9 select I[n] else Self(n1)+Self(n4)Self(n5): n in [1..30]]; // Vincenzo Librandi, Jul 25 2014


CROSSREFS

Sequence in context: A131883 A113452 A122461 * A092532 A073504 A092508
Adjacent sequences: A092530 A092531 A092532 * A092534 A092535 A092536


KEYWORD

nonn,easy


AUTHOR

N. J. A. Sloane, Apr 08 2004


STATUS

approved



