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A132064 Numbers multiplied by 4 and written backwards. 8
1, 4, 61, 442, 8671, 48643, 275491, 4691011, 44046781, 421781671, 4866217861, 44417846491, 469583176771, 4807072338781, 42155398282291, 461921395126861, 4447050855867481, 42996432430288771, 480551127927589171, 4866530171154022291, 46198061648602166491 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,2

LINKS

Alois P. Heinz, Table of n, a(n) for n = 1..1000

FORMULA

a(n) = reverse(4*a(n-1)) where a(1) = 1

Conjecture: a(n)^(1/n) tends to 10. - Vaclav Kotesovec, Jan 03 2020

EXAMPLE

a(4) = reverse(4*a(3)) = reverse(4*reverse(4*a(2))) = reverse(4*reverse(4*reverse(4*a(1)))) = reverse(4*reverse(4*4)) = reverse(4*61) = reverse(244) = 442

MAPLE

a:= proc(n) option remember; `if`(n=1, 1,

      (s-> parse(cat(s[-i]$i=1..length(s))))(""||(4*a(n-1))))

    end:

seq(a(n), n=1..30);  # Alois P. Heinz, Apr 09 2015

MATHEMATICA

NestList[IntegerReverse[4#]&, 1, 20] (* Requires Mathematica version 11 or later *) (* Harvey P. Dale, Dec 09 2017 *)

CROSSREFS

Cf. A036447 (*2), A163632 (*3), A045539 (*5), A132078 (*6), A132114 (*7), A132113 (*8), A133361 (*9).

Sequence in context: A129452 A131014 A118005 * A229666 A252973 A262654

Adjacent sequences:  A132061 A132062 A132063 * A132065 A132066 A132067

KEYWORD

base,nonn

AUTHOR

Rachit Agrawal (rachit_agrawal(AT)daiict.ac.in), Oct 30 2007

EXTENSIONS

More terms from Alois P. Heinz, Apr 09 2015

STATUS

approved

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Last modified September 23 20:42 EDT 2021. Contains 347617 sequences. (Running on oeis4.)