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A158242 Smallest n-digit number with distinct digits such that every k-digit substring (k <= n) taken from the left is divisible by k (k = 1..n). 7
1, 10, 102, 1024, 10245, 102456, 1024569, 12965408, 381654720, 3816547290 (list; graph; refs; listen; history; text; internal format)
OFFSET
1,2
COMMENTS
Years ago, the columnist Alex Bellos asked John Conway for some math puzzles for his column. A few days after Conway's death in 2020, Bellos published two of those puzzles. a(10) of this sequence is the solution to the second puzzle. See the Bellos (2020) link. - Alonso del Arte, Apr 21 2020
LINKS
Alex Bellos, Did you solve it? John Horton Conway, playful maths genius, The Guardian, April 20, 2020.
EXAMPLE
12965408, for instance, is in the sequence because 1|1, 2|12, 3|129, 4|1296, 5|12965, 6|129654, 7|1296540, 8|12965408. It's a(8).
CROSSREFS
Cf. A158240.
Sequence in context: A037503 A037680 A038378 * A147636 A191014 A147550
KEYWORD
nonn,base,fini,full
AUTHOR
Lekraj Beedassy, Mar 14 2009
EXTENSIONS
a(8), a(9) corrected by Ray Chandler, Mar 21 2009
STATUS
approved

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Last modified March 28 11:58 EDT 2024. Contains 371241 sequences. (Running on oeis4.)