cp's OEIS Frontend

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

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