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A321149 a(1) = 102735, a(n) = prime(n-1)*a(n-1) but products that are not in A010784 are first reduced as in A320486 (see comments); continue until zero is reached. 2
102735, 2547, 7641, 38205, 267435, 2941785, 8405, 1425, 205, 4715, 1675, 192, 7104, 9164, 394052, 18520, 981560, 579124, 24, 1608, 468, 316, 296, 24568, 186, 18042, 184, 18952, 7864, 8516, 962308, 36 (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.

102735 is the smallest of 785 A010784 terms that result in a 362-term sequence, the longest possible.

LINKS

Hans Havermann, Table of n, a(n) for n = 1..362

Hans Havermann, What's so special about 102735?

EXAMPLE

2 * 102735 = [205470] => 2547

3 * 2547 = 7641

5 * 7641 = 38205

7 * 38205 = 267435

11 * 267435 = 2941785

13 * 2941785 = [38243205] => 8405

17 * 8405 = [142885] => 1425

19 * 1425 = [27075] => 205

...

2417 * 40 = [96680] => 980

2423 * 980 = [2374540] => 23750

2437 * 23750 = [57878750] => 0

CROSSREFS

Cf. A010784, A321148, A320486.

Sequence in context: A034089 A146569 A081463 * A323604 A014884 A015330

Adjacent sequences:  A321146 A321147 A321148 * A321150 A321151 A321152

KEYWORD

nonn,fini,full,base

AUTHOR

Hans Havermann, Oct 28 2018

STATUS

approved

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Last modified October 23 17:32 EDT 2019. Contains 328373 sequences. (Running on oeis4.)