login
This site is supported by donations to The OEIS Foundation.

 

Logo


Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
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 * A014884 A015330 A250704

Adjacent sequences:  A321143 A321144 A321148 * A321153 A321155 A321178

KEYWORD

nonn,fini,full,base,changed

AUTHOR

Hans Havermann, Oct 28 2018

STATUS

approved

Lookup | Welcome | Wiki | Register | Music | Plot 2 | Demos | Index | Browse | More | WebCam
Contribute new seq. or comment | Format | Style Sheet | Transforms | Superseeker | Recent | More pages
The OEIS Community | Maintained by The OEIS Foundation Inc.

License Agreements, Terms of Use, Privacy Policy. .

Last modified November 18 01:03 EST 2018. Contains 317279 sequences. (Running on oeis4.)