OFFSET
0,2
COMMENTS
Linked to A029609 by a Catalan transform.
Hankel transform is (1, -15, 0, 0, 0, 0, 0, 0, 0, ...).
LINKS
G. C. Greubel, Table of n, a(n) for n = 0..1000
Index entries for linear recurrences with constant coefficients, signature (2).
FORMULA
a(n) = 5*2^(n-1) for n >= 1, a(0) = 1.
G.f.: (1 + 3*x)/(1 - 2*x). - Vladimir Joseph Stephan Orlovsky, Jun 21 2011
G.f.: G(0), where G(k)= 1 + 3*x/(1 - 2*x/(2*x + 3*x/G(k+1) )); (continued fraction). - Sergei N. Gladkovskii, Jul 03 2013
E.g.f.: (5*exp(2*x) - 3)/2. - Stefano Spezia, Feb 20 2023
MATHEMATICA
CoefficientList[Series[(1+3x)/(1-2x), {x, 0, 50}], x] (* Vladimir Joseph Stephan Orlovsky, Jun 21 2011 *)
Join[{1}, 5*2^(Range[40] -1)] (* G. C. Greubel, Nov 23 2021 *)
PROG
(PARI) a(n)=if(n, 5<<(n-1), 1) \\ Charles R Greathouse IV, Jan 17 2012
(Sage) [1]+[5*2^(n-1) for n in (1..50)] # G. C. Greubel, Nov 23 2021
CROSSREFS
KEYWORD
nonn,easy
AUTHOR
Philippe Deléham, Oct 30 2008
STATUS
approved