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A182557
a(n) = a(n-1)*2 + floor(sqrt(a(n-2))).
3
0, 1, 2, 5, 11, 24, 51, 106, 219, 448, 910, 1841, 3712, 7466, 14992, 30070, 60262, 120697, 241639, 483625, 967741, 1936177, 3873337, 7748065, 15498098, 30998979, 62001894, 124009355, 248026584, 496064303, 992144354, 1984310980, 3968653458, 7937351461, 15874765919
OFFSET
0,3
LINKS
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][[;; , 1]] (* Harvey P. Dale, Sep 30 2024 *)
PROG
(Python)
import math
prpr = 0
prev = 1
for n in range(55):
current = prev*2 + int(math.sqrt(prpr))
print(prpr, end=', ')
prpr = prev
prev = current
CROSSREFS
Sequence in context: A300277 A294378 A090764 * A027934 A336482 A134389
KEYWORD
nonn
AUTHOR
Alex Ratushnyak, May 05 2012
STATUS
approved