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A061580 a(1) = 1, a(n)= number obtained by replacing each digit of a(n-1) with four times its value. 1
1, 4, 16, 424, 16816, 42432424, 1681612816816, 42432424483242432424, 168161281681616321281681612816816, 42432424483242432424424128483242432424483242432424 (list; graph; refs; listen; history; text; internal format)
OFFSET
1,2
LINKS
Michael De Vlieger, Table of n, a(n) for n = 1..16
MATHEMATICA
NestList[FromDigits@ Flatten@ Map[IntegerDigits, 4*IntegerDigits[#]] &, 1, 9] (* Michael De Vlieger, Feb 25 2023 *)
CROSSREFS
Sequence in context: A067211 A156337 A000874 * A037976 A013138 A262546
KEYWORD
nonn,base,easy
AUTHOR
Amarnath Murthy, May 13 2001
EXTENSIONS
More terms from Larry Reeves (larryr(AT)acm.org) and Asher Auel, May 15 2001
a(9) corrected by N. J. A. Sloane, Jan 23 2017 at the suggestion of Carolyn Liao.
a(10) corrected by Sean A. Irvine, Feb 25 2023
STATUS
approved

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Last modified June 14 02:53 EDT 2024. Contains 373392 sequences. (Running on oeis4.)