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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 Cf. A061581, A061582, A061583, A061584, A061585, A061586, A061587. Sequence in context: A067211 A156337 A000874 * A037976 A013138 A262546 Adjacent sequences: A061577 A061578 A061579 * A061581 A061582 A061583 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.)