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

 Hints (Greetings from The On-Line Encyclopedia of Integer Sequences!)
 A193129 Number of spanning trees of the n-barbell graph. 1
 1, 1, 1, 9, 256, 15625, 1679616, 282475249, 68719476736, 22876792454961, 10000000000000000, 5559917313492231481, 3833759992447475122176, 3211838877954855105157369, 3214199700417740936751087616, 3787675244106352329254150390625 (list; graph; refs; listen; history; text; internal format)
 OFFSET 0,4 COMMENTS a(n) = A000272(n)^2 for n>=0. LINKS M. F. Hasler, Table of n, a(n) for n = 0..32 (corrected by Georg Fischer, Jan 20 2019) Eric Weisstein's World of Mathematics, Barbell Graph Eric Weisstein's World of Mathematics, Spanning Tree FORMULA a(0)=1 and a(n)=n^(2n-4) for n>=1 (from the comment and the formula for A000272). MATHEMATICA Table[n^(2 n - 4), {n, 3, 20}] PROG (PARI) A193129=n^(2*n-4) \\ M. F. Hasler, Apr 14 2015 CROSSREFS Cf. A000272. Sequence in context: A212290 A296950 A025133 * A183493 A183424 A160073 Adjacent sequences:  A193126 A193127 A193128 * A193130 A193131 A193132 KEYWORD nonn AUTHOR Eric W. Weisstein, Jul 16 2011 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 August 13 08:18 EDT 2022. Contains 356079 sequences. (Running on oeis4.)