The On-Line Encyclopedia of Integer Sequences (OEIS)

A018142 revision #16

A018142

Powers of fifth root of 10 rounded to nearest integer.

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

MATHEMATICA

Round[(10^(Range[0, 50]/5))] (* Paolo Xausa, Jul 02 2024 *)

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

editing