login
The OEIS is supported by the many generous donors to the OEIS Foundation.

 

Logo
Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A045716 a(n) is the binary order (A029837) of the n-th primorial number, A002110(n). 7
1, 3, 5, 8, 12, 15, 19, 24, 28, 33, 38, 43, 49, 54, 60, 65, 71, 77, 83, 89, 96, 102, 108, 115, 121, 128, 135, 141, 148, 155, 162, 169, 176, 183, 190, 198, 205, 212, 220, 227, 235, 242, 250, 257, 265, 273, 280, 288, 296, 304, 312, 319, 327, 335, 343, 351, 359 (list; graph; refs; listen; history; text; internal format)
OFFSET
1,2
COMMENTS
These orders determine the maximal numbers of unitary divisors valid for integers in given binary order ranges (see A046971).
LINKS
FORMULA
a(n) = A054850(n)+1, n >= 2.
a(n) = A070939(A002110(n)) for n>1. - Jachym Barvinek, Mar 22 2018
EXAMPLE
The sixth primorial number is 2*3*5*7*11*13 = 30030, which is in the interval [16385, 32768] = [2^14 + 1, 2^15], so its binary order is a(6)=15. [corrected by Jon E. Schoenfield, May 13 2018]
MATHEMATICA
Table[Ceiling@ Log2[Times @@ Prime@ Range@ n], {n, 57}] (* Michael De Vlieger, Feb 05 2017 *)
PROG
(PARI) a(n)=logint(prod(i=1, n, prime(i))-1, 2)+1 \\ Charles R Greathouse IV, Feb 06 2017
CROSSREFS
Sequence in context: A218485 A310029 A310030 * A236203 A122539 A310031
KEYWORD
nonn
AUTHOR
STATUS
approved

Lookup | Welcome | Wiki | Register | Music | Plot 2 | Demos | Index | Browse | More | WebCam
Contribute new seq. or comment | Format | Style Sheet | Transforms | Superseeker | Recents
The OEIS Community | Maintained by The OEIS Foundation Inc.

License Agreements, Terms of Use, Privacy Policy. .

Last modified July 7 17:39 EDT 2024. Contains 374112 sequences. (Running on oeis4.)