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A321148 a(1) = 24603, a(n) = n*a(n-1) but products that are not in A010784 are first reduced as in A320486 (see comments); continue until zero is reached. 1
24603, 49206, 4768, 19072, 95360, 572160, 4512, 309, 2781, 27810, 3591, 43092, 5019, 702, 153, 28, 476, 56, 1064, 180, 3780, 83160, 92680, 430, 175, 40, 18, 504, 4, 120, 3720, 94, 3102, 105468, 69180, 298, 26, 9, 351, 1, 41, 17, 731, 32164, 17380, 7480, 3160, 5680, 7830, 3915, 15, 780, 130, 72, 3960, 1760, 132, 75, 25, 15, 915, 56730, 570, 36480, 371, 286, 962, 541, 729, 513, 642, 6, 438, 341, 27, 5, 385, 0 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

At each step, integers that contain duplicated digits are reduced to terms of A010784 by erasing all digits that appear more than once and bunching up the digits that remain. Leading zeros are ignored and any number that disappears entirely becomes 0. See A320486.

24603 is the smallest of 1746 A010784 terms that result in a 78-term sequence, the longest possible.

LINKS

Table of n, a(n) for n=1..78.

Hans Havermann, What's so special about 102735?

EXAMPLE

2 * 24603 = 49206

3 * 49206 = [147618] => 4768

4 * 4768 = 19072

5 * 19072 = 95360

6 * 95360 = 572160

7 * 572160 = [4005120] => 4512

8 * 4512 = [36096] => 309

...

76 * 27 = [2052] => 5

77 * 5 = 385

78 * 385 = [30030] => 0

CROSSREFS

Cf. A010784, A321149, A320486.

Sequence in context: A188791 A195650 A189184 * A216069 A204481 A052356

Adjacent sequences:  A321142 A321143 A321144 * A321149 A321153 A321155

KEYWORD

nonn,fini,full,base,changed

AUTHOR

Hans Havermann, Oct 28 2018

STATUS

approved

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Last modified November 17 20:50 EST 2018. Contains 317278 sequences. (Running on oeis4.)