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A182558 a(n) = a(n-1)*2 - floor(sqrt(a(n-2))). 1
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 (list; graph; refs; listen; history; text; internal format)
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 A107250

Adjacent sequences:  A182555 A182556 A182557 * A182559 A182560 A182561

KEYWORD

nonn

AUTHOR

Alex Ratushnyak, May 05 2012

STATUS

approved

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Last modified February 19 10:40 EST 2018. Contains 299330 sequences. (Running on oeis4.)