0,3

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

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...

Cf. A140665.

Sequence in context: A214958 A161350 A342048 * A140665 A390315 A069024

Adjacent sequences: A108649 A108650 A108651 * A108653 A108654 A108655

base,easy,fini,nonn

Eric Angelini and Alexandre Wajnberg, Jul 06 2005

More terms from David Wasserman, May 20 2008

approved