OFFSET
1,2
COMMENTS
Does not increase monotonically.
LINKS
Michael De Vlieger, Table of n, a(n) for n = 1..10000
FORMULA
EXAMPLE
Between [2 and 6] is 4;
between [6 and 30] are 8, 16;
between [30 and 210] are 32, 64, 128;
between [210 and 2310] are 256, 512, 1024, 2048;
between [2310 and 30030] are 4096, 8192, 16384;
between [30030, 510510] are 32768, 65536, 131072, 262144.
So a(1), ..., a(6) = 1, 2, 3, 4, 3, 4, ...
From Michael De Vlieger, Jul 15 2017: (Start)
First and last positions of values seen in the first 10^5 terms:
Value First Last
1 1 1
2 2 2
3 3 5
4 4 8
5 7 15
6 12 27
7 20 51
8 35 90
9 57 161
10 102 294
11 182 542
12 323 995
13 585 1856
14 1061 3505
15 1943 6485
16 3521 12203
17 6606 22949
18 12297 43200
19 23051 81759
20 43578 (99999)
21 82296 (99997)
(End)
MATHEMATICA
a = Table[ Floor[ Log[2, Product[ Prime[i], {i, 1, n}]]], {n, 1, 110}]; Drop[a, 1] - Drop[a, -1]
(* Second program: *)
Differences@ Floor@ Log2@ FoldList[Times, Prime@ Range@ 105] (* Michael De Vlieger, Jul 15 2017 *)
CROSSREFS
KEYWORD
nonn
AUTHOR
Labos Elemer, Nov 22 2000
EXTENSIONS
Edited by Robert G. Wilson v, May 22 2003
STATUS
approved