OFFSET
0,2
REFERENCES
A. H. Beiler, Recreations in the Theory of Numbers, Dover, N.Y., 1964, pp. 194-196.
LINKS
Andrew Howroyd, Table of n, a(n) for n = 0..200
FORMULA
4*(n+1)*a(n) + (-23*n-1)*a(n-1) + 14*(2*n-3)*a(n-2) = 0. - R. J. Mathar, Feb 13 2015
-(n+1)*(9*n-8)*a(n) + 2*(9*n+1)*(2*n-1)*a(n-1) = 0. - R. J. Mathar, Feb 13 2015
G.f.: (4 - 7*x - 4*sqrt(1 - 4*x))/(x*sqrt(1 - 4*x)). - Ilya Gutkovskiy, Jun 13 2017
PROG
(Magma) [Catalan(n)*(9*n+1):n in [0..27] ]; // Marius A. Burtea, Jan 05 2020
(Magma) R<x>:=PowerSeriesRing(Rationals(), 30); (Coefficients(R!( (4-7*x-4*Sqrt(1-4*x))/(x*Sqrt(1-4*x)))))// Marius A. Burtea, Jan 05 2020
CROSSREFS
KEYWORD
easy,nonn
AUTHOR
Barry E. Williams, Dec 24 1999
EXTENSIONS
Terms a(21) and beyond from Andrew Howroyd, Jan 05 2020
STATUS
approved