A182558 a(n) = a(n-1)*2 - floor(sqrt(a(n-2))).

0, 1, 2, 3, 5, 9, 16, 29, 54, 103, 199, 388, 762, 1505, 2983, 5928, 11802, 23528, 46948, 93743, 187270, 374234, 748036, 1495461, 2990058, 5978894, 11956059, 23909673, 47815889, 95626889, 191246864, 382483950, 764954071, 1529888585, 3059749513

Offset

0,3

Links

Harvey P. Dale, Table of n, a(n) for n = 0..1000

Formula

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

Mathematica

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

Prog

(Python)
import math
prpr = 0
prev = 1
for n in range(55):
.  current = prev*2 - int(math.sqrt(prpr))
.  print prpr,
.  prpr = prev
.  prev = current

Crossrefs

Cf. A076677, A076678, A182557.

Sequence in context: A000050 A050253 A198518 * A298204 A265581 A335703

Adjacent sequences: A182555 A182556 A182557 * A182559 A182560 A182561

Keyword

nonn

Author

Alex Ratushnyak, May 05 2012

Status

approved