A173713 - OEIS

A173713

Similar to A173065 but without the constraint that the sequence be increasing.

1, 144, 43, 120, 80, 60, 5, 390, 87, 58, 56, 42, 9, 6, 160, 108, 72, 48, 4, 186, 124, 93, 100, 75, 90, 103, 114, 76, 57, 148, 111, 132, 104, 78, 117, 180, 110, 88, 96, 64, 176, 192, 126, 175, 140, 130, 195, 300, 98, 384, 153, 102, 68, 85, 204, 216, 162, 135, 234, 252, 168, 315, 150, 200, 420, 224, 432, 159, 106, 477, 906, 360, 330, 209, 342, 513, 266, 684, 152, 460, 138, 92, 69

(list; graph; refs; listen; history; text; internal format)

OFFSET

1,2

COMMENTS

The sequence was computed by D. S. McNeil.

Comments on A173713 and A173065 from Jack Brennen, Sep 21 2010: (Start)

Note that the sequence A173713 reaches 9-digit numbers fairly quickly, at index 451, but out to index 12000, it still does not reach 10-digit numbers.

The sequence A173065 (strictly increasing) seems to grow fairly slowly, with occasional big jumps, which isn't really surprising, I guess. It reaches 9-digit numbers at index 8060, and then grows very slowly.

The fact that 9-digit numbers usually get the job done is due to the relative abundance of divisors of 10^9 + 1 (32 divisors).

Note that 10^15 + 1 has 128 divisors, and so it seems very unlikely to me that you could ever reasonably calculate the sequence far enough to the point where 15-digit numbers would not suffice... (End)

REFERENCES

Eric Angelini, Posting to Sequence Fans Mailing List, Sep 21 2010

LINKS

Table of n, a(n) for n=1..83.

Eric Angelini, |a-b| divides concatenation [ab]

E. Angelini, |a-b| divides concatenation [ab] [Cached copy, with permission]

Jack Brennen, PARI Program

CROSSREFS

Cf. A173065.

Sequence in context: A147553 A030122 A057404 * A252485 A185589 A093159

Adjacent sequences: A173710 A173711 A173712 * A173714 A173715 A173716

KEYWORD

nonn

AUTHOR

N. J. A. Sloane, Nov 25 2010

STATUS

approved