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A002782 Concatenate the natural numbers, then partition into minimal strings so that each term divides the next.
(Formerly M2157 N0859)
4
1, 2, 34, 5678, 9101112131415161718192021222324252627282930313233343536 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,2

COMMENTS

What is the next term? (See A263623.)

a(6), if it exists, has more than 5888833 digits. - Lars Blomberg, Dec 01 2016

REFERENCES

Letter from the editor, J. Rec. Math., 3 (1970), 40-41.

N. J. A. Sloane, A Handbook of Integer Sequences, Academic Press, 1973 (includes this sequence).

N. J. A. Sloane and Simon Plouffe, The Encyclopedia of Integer Sequences, Academic Press, 1995 (includes this sequence).

LINKS

Table of n, a(n) for n=1..5.

Editor, J. Recreational Math., Letter, J. Rec. Math., 3 (1970), 40-41. [Annotated scanned copy]

EXAMPLE

1 divides 2 divides 34 divides 5678 divides 9101112131415161718192021222324252627282930313233343536.

PROG

(Haskell)

a002782 n = a002782_list !! (n-1)

a002782_list = f 1 1 (map toInteger $ tail a007376_list) where

   f x y (d:ds) | mod y x == 0 = y : f y d ds

                | otherwise    = f x (10*y + d) ds

-- Reinhard Zumkeller, Dec 17 2011

CROSSREFS

Cf. A007376, A258227, A263623.

See A007908 for a classic sequence of the same ilk.

Sequence in context: A255434 A206501 A183414 * A155205 A303444 A230244

Adjacent sequences:  A002779 A002780 A002781 * A002783 A002784 A002785

KEYWORD

nonn,base,nice

AUTHOR

N. J. A. Sloane.

STATUS

approved

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Last modified January 17 19:58 EST 2019. Contains 319251 sequences. (Running on oeis4.)