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!)
A048642 Partial products of A003188 (Gray code). 3
1, 1, 3, 6, 36, 252, 1260, 5040, 60480, 786240, 11793600, 165110400, 1651104000, 18162144000, 163459296000, 1307674368000, 31384184832000, 784604620800000, 21184324761600000, 550792443801600000, 16523773314048000000 (list; graph; refs; listen; history; text; internal format)
OFFSET
0,3
LINKS
FORMULA
a(0) = 1, a(n) = product(XOR(j, floor(j/2)), j=1..n).
a((2^n)-1) = A000142((2^n)-1) for all n.
MATHEMATICA
Join[{1}, FoldList[Times, Table[BitXor[n, Floor[n/2]], {n, 20}]]] (* Harvey P. Dale, Oct 05 2016 *)
PROG
(PARI) a(n) = prod(i=1, n, bitxor(i, i>>1)); \\ Michel Marcus, Apr 22 2013, Oct 02 2015
CROSSREFS
Sequence in context: A211895 A240986 A120595 * A264702 A077532 A174666
KEYWORD
easy,nonn
AUTHOR
Antti Karttunen, Jul 14 1999
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 March 18 22:56 EDT 2024. Contains 370952 sequences. (Running on oeis4.)