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!)
A168431 General number of transpositions of n objects with repetitions. 0

%I #3 Mar 30 2012 18:52:37

%S 1,2,9,46,245,1601

%N General number of transpositions of n objects with repetitions.

%F Apparently a(n)=A005651(n)-1, n>1. [From _R. J. Mathar_, Nov 26 2009]

%e a(1)=1!/1!=1 because A035294(1)=1; a(2)=2!/(1!*1!)=2 because A035294(2)=1; a(3)=3!/(1!*1!*1!)+3!/(2!*1!)=9 because A035294(3)=2; a(4)=4!/(1!*1!*1!*1!)+4!/(2!*1!*1!)+4!/(2!*2!)+4!/(3!*1!)=46 because A035294(4)=4; a(5)=5!/(1!*1!*1!*1!*1!)+5!/(2!*1!*1!*1!)+5!/(2!*2!*1!)+5!/(3!*1!*1!)+5!/(3!*2!)+5!/(4!*1!)=245 because A035294(5)=6; a(6)=6!/(1!*1!*1!*1!*1!*1!)+6!/(2!*1!*1!*1!*1!)+6!/(2!*2!*1!*1!)+6!/(2!*2!*2!)+6!/(3!*1!*1!*1!)+6!/(3!*2!*1!)+6!/(3!*3!)+6!/(4!*1!*1!)+6!/(4!*2!)+6!/(5!*1!)=1601 because A035294(6)=10.

%Y Cf. A035294.

%Y Cf. A036038. [From _R. J. Mathar_, Nov 26 2009]

%K nonn

%O 1,2

%A _Juri-Stepan Gerasimov_, Nov 25 2009

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 April 24 19:36 EDT 2024. Contains 371962 sequences. (Running on oeis4.)