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A163501
Lexicographically earliest sequence of distinct positive integers such that a(n) shares no digit with a(a(n)) for all n.
4
2, 1, 4, 3, 6, 5, 8, 7, 10, 9, 12, 30, 14, 20, 16, 22, 18, 23, 21, 31, 33, 34, 40, 25, 36, 27, 35, 29, 37, 41, 42, 38, 44, 50, 46, 45, 48, 47, 43, 51, 52, 53, 55, 56, 60, 57, 58, 59, 54, 61, 62, 63, 64, 66, 67, 70, 68, 69, 71, 72, 73, 74, 75, 77, 76, 78, 80, 79, 81, 82, 83, 84
OFFSET
1,1
COMMENTS
This is an example of a sequence whose initial behavior is quite different from its limiting behavior. It starts out looking as though most numbers will appear in the sequence, but in fact it has density 0. It can't include any number that has all nine nonzero digits, and those have density 1. - Franklin T. Adams-Watters, Apr 03 2009
LINKS
EXAMPLE
a(1)=2 shares no digit with a(a(1))=a(2)=1;
a(2)=1 shares no digit with a(a(2))=a(1)=2; ...
a(11)=12 shares no digit with a(a(11))=a(12)=30, etc.
In building the sequence, always use the smallest available positive integer not yet present in the sequence.
CROSSREFS
Cf. A152200 (complement), A152208 (a variant), A152209.
Sequence in context: A014681 A103889 A137805 * A306229 A375757 A096779
KEYWORD
base,nonn
AUTHOR
Eric Angelini, Jul 29 2009
EXTENSIONS
Terms discussed, checked and computed by Paolo P. Lava, Jacques Tramu and Farideh Firoozbakht
Edited by Max Alekseyev, Feb 11 2012
STATUS
approved