OFFSET
0,2
LINKS
N. J. A. Sloane, Transforms
Index entries for linear recurrences with constant coefficients, signature (2,2,-2,-1,1).
FORMULA
G.f.: -1/(x^5-x^4-2*x^3+2*x^2+2*x-1).
EXAMPLE
a(3) = 14 = (3, 3, 1, 1) * (1, 1, 2, 6) = (3 + 3 + 2 + 6).
MAPLE
b:= proc(n) local m;
m:= ceil((n+1)/2);
m*(m+1)/2
end:
invtr:= proc(b)
local a;
a:= proc(n) option remember; local i;
`if`(n<1, 1, add(a(n-i) *b(i-1), i=1..n+1))
end;
end:
a:= invtr(b):
seq(a(n), n=0..30);
MATHEMATICA
LinearRecurrence[{2, 2, -2, -1, 1}, {1, 2, 6, 14, 35}, 30] (* Jean-François Alcover, Nov 28 2020 *)
CROSSREFS
KEYWORD
nonn,easy
AUTHOR
Gary W. Adamson, Dec 21 2010
EXTENSIONS
Edited by Alois P. Heinz, Dec 25 2010
STATUS
approved