A236857 Each n occurs the least common multiple (LCM) of {1, 2, ..., n} (= A003418(n)) times.

0, 1, 2, 2, 3, 3, 3, 3, 3, 3, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 6, 6, 6, 6, 6

Offset

0,3

Comments

Least k such that A236856(k) >= n.

Zero occurs once at a(0), because A003418(0)=1 by definition.

Useful when computing irregular tables like A238280, as a(n) gives the row index of the n-th term in such sequences. Note that as A238280 begins with row 1, it starts referring to this sequence only from a(1)=1 onward.

Links

Antti Karttunen, Rows 0..10 of the table, flattened

Example

Can be viewed as an irregular table, where each row n (starting from row zero) contains A003418(n) copies of n:
0;
1;
2, 2;
3, 3, 3, 3, 3, 3;
4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4;
...

Mathematica

Join[{0}, Flatten[Table[PadRight[{}, LCM@@Range[n], {n}], {n, 6}]]] (* Harvey P. Dale, Jul 29 2021 *)

Prog

(Scheme, with Antti Karttunen's IntSeq-library)
(define A236857 (LEAST-GTE-I 0 0 A236856))

Crossrefs

Cf. A003418, A084556, A236856, A236858.

Sequence in context: A071578 A364800 A157791 * A156874 A294234 A078767

Adjacent sequences: A236854 A236855 A236856 * A236858 A236859 A236860

Keyword

nonn,tabf

Author

Antti Karttunen, Feb 27 2014

Status

approved