A139281 - OEIS

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A139281

If all digits are the same mod 3, stop; otherwise write down the number formed by the 1 mod 3 digits and the number formed by the 2 mod 3 digits and the number formed by the 3 mod 3 digits and multiply them; repeat.

0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 0, 11, 2, 3, 14, 5, 6, 17, 8, 9, 0, 2, 22, 6, 8, 25, 2, 14, 28, 8, 30, 3, 6, 33, 2, 5, 36, 2, 8, 39, 0, 41, 8, 2, 44, 0, 8, 47, 6, 36, 0, 5, 52, 5, 0, 55, 30, 5, 58, 0, 60, 6, 2, 63, 8, 30, 66, 8, 6, 69, 0, 71, 14, 2, 74, 5, 8, 77, 30, 63, 0, 8, 82, 8, 6, 85, 6, 30

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OFFSET

0,3

COMMENTS

Modulo 3 analog of A059707. The 1 mod 3 digits = {1,4,7}, 2 mod 3 digits = {2,5,8}, 3 mod 3 digits = {0, 3, 6, 9}. The fixed points begin: 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 11, 14, 17, 22, 25, 28, 30, 33, 36, 39, 41, 44, 47, 52, 55, 58.

LINKS

Table of n, a(n) for n=0..87.

EXAMPLE

a(57) = 5 because 5 and 7 are different mod 3, so 5*7 = 35; 3 and 5 are different mod 3, so 3*5 = 15; 1 and 5 are different mod 3, so 1*5 = 5, which is a fixed point.

CROSSREFS

Cf. A010872, A059707, A059708, A059717.

Sequence in context: A195833 A257294 A330970 * A059707 A256754 A265525

Adjacent sequences: A139278 A139279 A139280 * A139282 A139283 A139284

KEYWORD

base,easy,nonn

AUTHOR

Jonathan Vos Post, Jun 06 2008

EXTENSIONS

a(52) corrected and sequence extended by Sean A. Irvine, Sep 03 2009

STATUS

approved