

A198802


Number of closed paths of length n whose steps are 18th roots of unity, U_18(n).


1



1, 0, 18, 36, 918, 5400, 82800, 801360, 10907190, 132053040, 1802041668, 24199809480, 340640607384, 4834708246368, 70229958125184, 1032223723667136, 15391538570569590, 231935110984687968, 3531542904056225916, 54244559313713885688, 839979883121036697468
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OFFSET

0,3


COMMENTS

U_18(n), comment in article: For each m >= 1, the sequence (U_m(N)), N >= 0 is Precursive but is not algebraic when m > 2.


LINKS



FORMULA

E.g.f.: g(x)^3 where g(x) is the e.g.f. of A002898.


PROG

(PARI) seq(n)={Vec(serlaplace(sum(k=0, n, if(k, 2, 1)*(x^k*besseli(k, 2*x + O(x^(nk+1)))/k!)^3)^3))} \\ Andrew Howroyd, Nov 01 2018


CROSSREFS



KEYWORD

nonn


AUTHOR



STATUS

approved



