|
%I M2157 N0859 #34 Jan 29 2022 01:01:43
%S 1,2,34,5678,9101112131415161718192021222324252627282930313233343536
%N Concatenate the natural numbers, then partition into minimal strings so that each term divides the next.
%C What is the next term? (See A263623.)
%C a(6), if it exists, has more than 5888833 digits. - _Lars Blomberg_, Dec 01 2016
%D Letter from the editor, J. Rec. Math., 3 (1970), 40-41.
%D N. J. A. Sloane, A Handbook of Integer Sequences, Academic Press, 1973 (includes this sequence).
%D N. J. A. Sloane and Simon Plouffe, The Encyclopedia of Integer Sequences, Academic Press, 1995 (includes this sequence).
%H Editor, J. Recreational Math., <a href="/A002782/a002782.pdf">Letter</a>, J. Rec. Math., 3 (1970), 40-41. [Annotated scanned copy]
%e 1 divides 2 divides 34 divides 5678 divides 9101112131415161718192021222324252627282930313233343536.
%o (Haskell)
%o a002782 n = a002782_list !! (n-1)
%o a002782_list = f 1 1 (map toInteger $ tail a007376_list) where
%o f x y (d:ds) | mod y x == 0 = y : f y d ds
%o | otherwise = f x (10*y + d) ds
%o -- _Reinhard Zumkeller_, Dec 17 2011
%Y Cf. A007376, A258227, A263623.
%Y See A007908 for a classic sequence of the same ilk.
%K nonn,base,nice
%O 1,2
%A _N. J. A. Sloane_
| 