A321149 - OEIS

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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.

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

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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