OFFSET
0,1
LINKS
Georg Fischer, Table of n, a(n) for n = 0..1000
I. Amburg, K. Dasaratha, L. Flapan, T. Garrity, C. Lee, C. Mihailak, N. Neumann-Chun, S. Peluse, M. Stoffregen, Stern Sequences for a Family of Multidimensional Continued Fractions: TRIP-Stern Sequences, arXiv:1509.05239 [math.CO], 17 Sep 2015.
Index entries for linear recurrences with constant coefficients, signature (2,4,-6).
FORMULA
G.f.: ( 3+2*x-7*x^2 ) / ( 1-2*x-4*x^2+6*x^3 ). - R. J. Mathar, Dec 02 2016
MAPLE
A278615T := proc(n)
option remember;
local an, nrecur ;
if n = 1 then
[1, 1, 1] ;
else
an := procname(floor(n/2)) ;
if type(n, 'even') then
# apply F0
[op(1, an)+ op(3, an), op(3, an), op(2, an)] ;
else
# apply F1
[op(1, an), op(1, an)+ op(3, an), op(2, an)] ;
end if;
end if;
end proc;
A278615 := proc(n)
local a, l;
a := 0 ;
for l from 2^n to 2^(n+1)-1 do
L := A278615T(l) ;
a := a+ L[1]+L[2]+L[3] ;
end do:
a ;
end proc: # R. J. Mathar, Dec 02 2016
MATHEMATICA
LinearRecurrence[{2, 4, -6}, {3, 8, 21}, 20] (* Jean-François Alcover, Nov 22 2017, after R. J. Mathar's g.f. *)
CROSSREFS
KEYWORD
nonn
AUTHOR
Ilya Amburg, Nov 23 2016
EXTENSIONS
More terms from R. J. Mathar, Dec 02 2016
STATUS
approved