A330398 - OEIS

A330398

For any n > 0, let S_n(0) be the concatenation of the numbers in the range 1..n (in increasing order); for k=1..n, S_n(k) is obtained by removing the rightmost occurrence of k in S_n(k-1), if any; a(n) is the numerical value of S_n(n) (or 0 if S_n(n) is empty).

0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 31, 3411, 345111, 34561111, 3456711111, 345678111111, 34567891111111, 1234567891011111, 1234567891111110, 1234567891111110, 14567891111102, 14567891111022, 14567891110222, 14567891112222, 14567891122222, 14567891222222

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OFFSET

1,13

COMMENTS

In other words, we concatenate the first n positive numbers, and then we decimate them from the right; a(n) is what remains at the end of this procedure.

LINKS

Rémy Sigrist, Table of n, a(n) for n = 1..1341

Rémy Sigrist, C# program for A330398

EXAMPLE

For n = 13:

- we have:

k S_13(k)

-- -----------------

0 12345678910111213

1 1234567891011123

2 123456789101113

3 12345678910111