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

 Hints (Greetings from The On-Line Encyclopedia of Integer Sequences!)
 A296144 Number of configurations, excluding reflections and color swaps, of n beads each of four colors on a string. 3
 1, 65, 7780, 1315825, 244448316, 48099214856, 9844135755168, 2074189508907945, 446932339677117580, 98028351499011470680, 21813996435165740009568, 4912693780465467348590056, 1117598703447726807428962400, 256444915320263078585645544000, 59283681793041084579875939892480, 13794224341895239072712767055117865 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,2 COMMENTS Power Group Enumeration applies here. REFERENCES E. Palmer and F. Harary, Graphical Enumeration, Academic Press, 1973. LINKS Table of n, a(n) for n=1..16. Marko Riedel et al., Unique rows of pebbles FORMULA With Z(S_{q,|m}) = [w^q] exp(Sum_{d|m} a_d w^d/d) and parameters n,k we have for nk even, (1/2) ((nk!)/k!/n!^k + (nk/2)! 2^(nk/2) [a_2^(nk/2)] Z(S_{k,|2})(Z_{n,|2}, a_2^n/n!) and for nk odd, (1/2) ((nk!)/k!/n!^k + ((nk-1)/2)! 2^((nk-1)/2) [a_1 a_2^((nk-1)/2)] Z(S_{k,|2})(Z_{n,|2}, a_2^n/n!). This sequence has k=4. CROSSREFS Cf. A045723, A296143, A296145, A296146. Sequence in context: A118707 A282839 A144661 * A251150 A176370 A093265 Adjacent sequences: A296141 A296142 A296143 * A296145 A296146 A296147 KEYWORD nonn AUTHOR Marko Riedel, Dec 05 2017 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.

Last modified April 15 04:16 EDT 2024. Contains 371667 sequences. (Running on oeis4.)