login
A120171
a(n) = 2 + floor((1 + Sum_{j=1..n-1} a(j))/5)
2
2, 2, 3, 3, 4, 5, 6, 7, 8, 10, 12, 14, 17, 20, 24, 29, 35, 42, 50, 60, 72, 87, 104, 125, 150, 180, 216, 259, 311, 373, 448, 537, 645, 774, 929, 1114, 1337, 1605, 1926, 2311, 2773, 3328, 3993, 4792, 5750, 6900, 8280, 9936, 11923, 14308, 17170, 20604, 24724, 29669
OFFSET
1,1
LINKS
MATHEMATICA
f[s_] := Append[s, Floor[(11 + Plus @@ s)/5]]; Nest[f, {2}, 53] (* Robert G. Wilson v, Jul 08 2006 *)
PROG
(Magma)
function f(n, a, b)
t:=0;
for k in [1..n-1] do
t+:= a+Floor((b+t)/5);
end for;
return t;
end function;
g:= func< n, a, b | f(n+1, a, b)-f(n, a, b) >;
A120171:= func< n | g(n, 2, 1) >;
[A120171(n): n in [1..60]]; // G. C. Greubel, Dec 25 2023
(SageMath)
@CachedFunction
def f(n, p, q): return p + (q +sum(f(k, p, q) for k in range(1, n)))//5
def A120171(n): return f(n, 2, 1)
[A120171(n) for n in range(1, 61)] # G. C. Greubel, Dec 25 2023
CROSSREFS
KEYWORD
nonn
AUTHOR
Graeme McRae, Jun 10 2006
EXTENSIONS
More terms from Robert G. Wilson v, Jul 08 2006
STATUS
approved