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A173660 Smallest integer not yet present such that [a(n)+a(n+1)] divides the concatenation [a(n),a(n+1)]. 1
1, 2, 4, 5, 10, 8, 14, 7, 26, 13, 20, 16, 17, 34, 32, 12, 6, 3, 24, 30, 15, 18, 9, 72, 27, 54, 45, 36, 63, 126, 28, 35, 42, 21, 56, 43, 86, 136, 51, 48, 40, 50, 25, 74, 37, 62, 31, 68, 64, 80, 19, 38, 61, 122, 76, 23, 46, 53, 106, 92, 115, 218, 109, 224, 84 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,2

REFERENCES

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

LINKS

Alois P. Heinz, Table of n, a(n) for n = 1..10000

EXAMPLE

1+2 divides 12    ->  12/3=4

2+4 divides 24    ->  24/6=4

4+5 divides 45    ->  45/9=5

5+10 divides 510  -> 510/15=34

10+8 divides 108  -> 108/18=6

8+14 divides 814  -> 814/22=37

...

MAPLE

ina:= proc() false end:

ina(1):= true: mina:= 2;

a:= proc(n) option remember; global mina; local k;

      if n=1 then 1

    else for k from mina while ina(k) or

           irem(parse(cat(a(n-1), k)), a(n-1)+k)<>0 do od;

         ina(k):= true; while ina(mina) do mina:= mina+1 od;

         k

      fi

    end:

seq(a(n), n=1..70);  # Alois P. Heinz, Sep 30 2011

CROSSREFS

Sequence in context: A232616 A125728 A276608 * A335315 A307805 A189767

Adjacent sequences:  A173657 A173658 A173659 * A173661 A173662 A173663

KEYWORD

nonn,base

AUTHOR

N. J. A. Sloane, Nov 24 2010

EXTENSIONS

Corrected and extended by Alois P. Heinz, Sep 30 2011

STATUS

approved

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Last modified July 15 23:32 EDT 2020. Contains 335774 sequences. (Running on oeis4.)