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A236857
Each n occurs the least common multiple (LCM) of {1, 2, ..., n} (= A003418(n)) times.
5
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
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
KEYWORD
nonn,tabf
AUTHOR
Antti Karttunen, Feb 27 2014
STATUS
approved