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

Author

Antti Karttunen, Feb 27 2014

Keywords

• nonn
• tabf

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.

Examples

			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;
...
		

Links

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

Crossrefs

Cf. A003418, A084556, A236856, A236858.

Programs

Mathematica

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