

A097950


G.f.: (1+x^5+x^10)/((1x)*(1x^3)).


0



1, 1, 1, 2, 2, 3, 4, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51, 52, 53, 54, 55, 56, 57, 58, 59, 60, 61, 62, 63, 64, 65, 66, 67, 68, 69, 70, 71, 72
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OFFSET

0,4


LINKS

Table of n, a(n) for n=0..75.
G. Nebe, E. M. Rains and N. J. A. Sloane, SelfDual Codes and Invariant Theory, Springer, Berlin, 2006.
E. M. Rains and N. J. A. Sloane, Selfdual codes, pp. 177294 of Handbook of Coding Theory, Elsevier, 1998 (Abstract, pdf, ps).
Index entries for Molien series
Index entries for linear recurrences with constant coefficients, signature (2,1).


FORMULA

Molien series is (1+x^10+x^20)/((1x^2)*(1x^6)).
a(n) = n  3 for n > 7. [Charles R Greathouse IV, Oct 27 2011]


MATHEMATICA

CoefficientList[Series[(1+x^5+x^10)/((1x)*(1x^3)), {x, 0, 80}], x] (* or *) LinearRecurrence[{2, 1}, {1, 1, 1, 2, 2, 3, 4, 4, 5}, 80] (* Harvey P. Dale, Oct 11 2015 *)


PROG

(PARI) a(n)=if(n>7, n3, [1, 1, 1, 2, 2, 3, 4, 4][n+1]) \\ Charles R Greathouse IV, Oct 27 2011


CROSSREFS

Sequence in context: A241948 A051068 A050294 * A011885 A211524 A008672
Adjacent sequences: A097947 A097948 A097949 * A097951 A097952 A097953


KEYWORD

nonn,easy


AUTHOR

N. J. A. Sloane, Sep 06 2004


STATUS

approved



