OFFSET
0,2
REFERENCES
N. J. A. Sloane and Simon Plouffe, The Encyclopedia of Integer Sequences, Academic Press, 1995 (includes this sequence).
LINKS
T. D. Noe, Table of n, a(n) for n=0..200
F. T. Howard, Properties of the van der Pol numbers and polynomials, R. Reine Angew. Math., 260 (1973), 35-46.
FORMULA
E.g.f. for fractions: x^3/( 6*x*(exp(x)+1)-12*(exp(x)-1) ).
EXAMPLE
MAPLE
G:=x^3/(6*x*(exp(x)+1)-12*(exp(x)-1)):Gser:=series(G, x=0, 35):1, seq(denom(n!*coeff(Gser, x^n)), n=1..31); # Emeric Deutsch, Dec 23 2004
MATHEMATICA
max = 26; g[x_] = x^3/(6*x*(E^x + 1) - 12*(E^x - 1)); Denominator[ CoefficientList[ Series[ g[x], {x, 0, max}], x]*Range[0, max]!](* Jean-François Alcover, Nov 17 2011, after g.f. *)
CROSSREFS
KEYWORD
nonn,frac,nice,easy
AUTHOR
EXTENSIONS
More terms from Emeric Deutsch, Dec 23 2004
STATUS
approved