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!)
A062206 a(n) = n^(2n). 26
1, 1, 16, 729, 65536, 9765625, 2176782336, 678223072849, 281474976710656, 150094635296999121, 100000000000000000000, 81402749386839761113321, 79496847203390844133441536, 91733330193268616658399616009, 123476695691247935826229781856256 (list; graph; refs; listen; history; text; internal format)
OFFSET
0,3
COMMENTS
a(n) is also the number of sequences of length 2n on n symbols. - Washington Bomfim, Oct 06 2009
a(n) is the number of endofunctions on [n] that map each even number to an even number and each odd number to an odd number. - Enrique Navarrete, Sep 30 2022
LINKS
Winston de Greef, Table of n, a(n) for n = 0..213 (first 101 terms from Harry J. Smith)
FORMULA
a(n) = A000312(n)^2 = A000290(n)^n.
(-1)^n*determinant of the 2n X 2n matrix M_(i, j) = i+j if (i + j) is a multiple of n, M_(i, j) = 1 otherwise. - Benoit Cloitre, Aug 06 2003
a(n) = A155955(n,n) = A000290(A000312(n)). - Reinhard Zumkeller, Jan 31 2009
a(n) = n! * [x^n] 1/(1 + LambertW(-n*x)). - Ilya Gutkovskiy, Oct 03 2017
Sum_{n>=1} 1/a(n) = A086648. - Amiram Eldar, Nov 16 2020
MATHEMATICA
f[n_]:=n^(2*n); Join[{1}, f[Range[20]]] (* Vladimir Joseph Stephan Orlovsky, Feb 19 2011 *)
PROG
(PARI) a(n) = n^(2*n); \\ Harry J. Smith, Aug 02 2009
(Python)
def A062206(n): return n**(n<<1) # Chai Wah Wu, Nov 18 2022
CROSSREFS
Column k=0 of A245910 and A245980.
Sequence in context: A220809 A221023 A171736 * A209537 A086701 A218297
KEYWORD
easy,nonn
AUTHOR
Jason Earls, Jun 13 2001
EXTENSIONS
Initial term corrected by Reinhard Zumkeller, Jan 30 2009
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 17 13:30 EDT 2024. Contains 374377 sequences. (Running on oeis4.)