OFFSET
0,2
LINKS
G. C. Greubel, Table of n, a(n) for n = 0..1000
FORMULA
a(n) = 1 + 2 * Sum_{k=1..n} a(floor(k/2)). - Ilya Gutkovskiy, Aug 15 2021
MATHEMATICA
a[n_]:= a[n] = If[n==0, 1, a[n-1] + 2*a[Floor[n/2]]];
Table[a[n], {n, 0, 50}] (* G. C. Greubel, Feb 10 2021 *)
PROG
(PARI) a(n) = if (n==0, 1, a(n-1)+2*a(n\2)); \\ Michel Marcus, Feb 04 2021
(Python)
def a(n): return 1 if n == 0 else a(n-1) + 2*a(n//2)
print([a(n) for n in range(44)]) # Michael S. Branicky, Feb 04 2021
(Magma) [1] cat [n le 2 select 3^n else Self(n-1) + 2*Self(Floor(n/2)): n in [1..51]]; // G. C. Greubel, Feb 10 2021
KEYWORD
nonn
AUTHOR
Reinhard Zumkeller, Feb 16 2002
EXTENSIONS
Name corrected by and more terms from Michael S. Branicky, Feb 04 2021
STATUS
approved