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A108652
Self-erasure surviving numbers.
1
0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 20, 23, 24, 25, 26, 27, 28, 29, 30, 32, 36, 37, 38, 39, 40, 42, 45, 46, 47, 48, 49, 50, 51, 54, 58, 59, 60, 62, 64, 67, 68, 69, 70, 71, 73, 76, 80, 83, 84, 86, 89, 90, 91, 92, 93, 94, 95, 98, 114, 116, 117, 118, 119, 124, 127, 128, 129, 130, 131
OFFSET
0,3
COMMENTS
The sequence is finite.
There are some n such that n appears between two erased digits, but all such occurrences of n later have one of their digits erased. The first example is 71. Such numbers are included in this version. If they are excluded we get A140665. - David Wasserman, May 20 2008
The sequence is finite because there can be no more than ten digits between consecutive erasures. The largest member is 9999986420. - David Wasserman, May 20 2008
EXAMPLE
Take an integer like 36, for example. Concatenate an infinite number of copies of itself: 363636363636363636363636... Put your left index on the first digit (3), jump 3 digits (to the right) with your right index and erase the digit you're landing on (3). Move your left finger (to the right) on the next visible digit (6). Jump thus 6 digits (to the right) with your right finger and erase the digit you're landing on, etc. If the number you started with (36) appears suddenly between two erased digits, you have a "Self-erasure surviving number".
In the example below, the erased digits are between parentheses:
3636(3)63(6)3(6)36(3)(6)3(6)3636363636...
CROSSREFS
Cf. A140665.
Sequence in context: A214958 A161350 A342048 * A140665 A069024 A175396
KEYWORD
base,easy,fini,nonn
AUTHOR
EXTENSIONS
More terms from David Wasserman, May 20 2008
STATUS
approved