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A018142 Powers of fifth root of 10 rounded to nearest integer. 3
1, 2, 3, 4, 6, 10, 16, 25, 40, 63, 100, 158, 251, 398, 631, 1000, 1585, 2512, 3981, 6310, 10000, 15849, 25119, 39811, 63096, 100000, 158489, 251189, 398107, 630957, 1000000, 1584893, 2511886, 3981072, 6309573 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,2

LINKS

Chai Wah Wu, Table of n, a(n) for n = 0..1000

FORMULA

a(n) = round(10^(n/5)). - Wesley Ivan Hurt, Jun 23 2015

MAPLE

A018142:=n->round(10^(n/5)): seq(A018142(n), n=0..50); # Wesley Ivan Hurt, Jun 23 2015

PROG

(Python)

from gmpy2 import iroot_rem

def A018142(n):

    i, j = iroot_rem(10**n, 5)

    return int(i) + int(32*j >= 10*i*(4*i*(2*i*(i + 1) + 1) + 1) + 1) # Chai Wah Wu, Aug 18 2016

CROSSREFS

Sequence in context: A072944 A024722 A024965 * A173697 A017986 A343304

Adjacent sequences:  A018139 A018140 A018141 * A018143 A018144 A018145

KEYWORD

nonn,easy

AUTHOR

N. J. A. Sloane

STATUS

approved

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Last modified May 23 18:08 EDT 2022. Contains 353993 sequences. (Running on oeis4.)