A182558 - OEIS

%I #12 Dec 26 2024 19:52:58

%S 0,1,2,3,5,9,16,29,54,103,199,388,762,1505,2983,5928,11802,23528,

%T 46948,93743,187270,374234,748036,1495461,2990058,5978894,11956059,

%U 23909673,47815889,95626889,191246864,382483950,764954071,1529888585,3059749513

%N a(n) = a(n-1)*2 - floor(sqrt(a(n-2))).

%H Harvey P. Dale, <a href="/A182558/b182558.txt">Table of n, a(n) for n = 0..1000</a>

%F a(0)=0, a(1)=1, a(n) = a(n-1)*2 - floor(sqrt(a(n-2))).

%t nxt[{a_,b_}]:={b,2b-Floor[Sqrt[a]]}; NestList[nxt,{0,1},40][[All,1]] (* _Harvey P. Dale_, Apr 29 2017 *)

%o (Python)

%o import math

%o prpr = 0

%o prev = 1

%o for n in range(55):

%o     current = prev*2 - int(math.sqrt(prpr))

%o     print(prpr, end=', ')

%o     prpr = prev

%o     prev = current

%Y Cf. A076677, A076678, A182557.

%K nonn

%O 0,3

%A _Alex Ratushnyak_, May 05 2012