A205770 Powers of fifth root of 100, rounded to the nearest integer.

1, 3, 6, 16, 40, 100, 251, 631, 1585, 3981, 10000, 25119, 63096, 158489, 398107, 1000000, 2511886, 6309573, 15848932, 39810717, 100000000, 251188643, 630957344, 1584893192, 3981071706, 10000000000, 25118864315, 63095734448, 158489319246, 398107170553, 1000000000000

Offset

0,2

Comments

The fifth root of 100, known as Pogson's ratio, is the ratio between successive stellar magnitudes.

Links

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

Eric Weisstein's World of Mathematics, Pogson's Ratio

Mathematica

Table[Round[100^(n/5)], {n, 0, 30}] (* G. C. Greubel, Jan 14 2018 *)

Prog

(PARI) a(n)=round(100^(n/5)) \\ Charles R Greathouse IV, Jan 31 2012
(Python)
from gmpy2 import iroot
def A205770(n):
    m = 100**n
    i = iroot(m, 5)[0]
    return int(i) + int(32*m >= (1+2*i)**5) # Chai Wah Wu, Aug 16 2016
(Magma) [Round(100^(n/5)): n in [0..30]]; // G. C. Greubel, Jan 14 2018

Crossrefs

Bisection of A018142, ratio is A189824.

Sequence in context: A188442 A046211 A239980 * A301959 A018022 A166536

Adjacent sequences: A205767 A205768 A205769 * A205771 A205772 A205773

Keyword

nonn,easy

Author

Franklin T. Adams-Watters, Jan 31 2012

Status

approved