A002782 Concatenate the natural numbers, then partition into minimal strings so that each term divides the next.

1, 2, 34, 5678, 9101112131415161718192021222324252627282930313233343536

Offset: 1

Author

N. J. A. Sloane

Keywords

• nonn
• base
• nice

Comments

What is the next term? (See A263623.)

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

Examples

			1 divides 2 divides 34 divides 5678 divides 9101112131415161718192021222324252627282930313233343536.
		

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

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

Crossrefs

Cf. A007376, A258227, A263623.

See A007908 for a classic sequence of the same ilk.

Programs

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