|
Search: id:A130449
|
|
|
| A130449 |
|
a(1) = 1; a(n) = 2^(2*n+1)+2*a(n-1)+1 |
|
+0
1
|
|
| 1, 17, 1089, 278785, 285475841, 1169309044737, 19157959388971009, 1255536026515604045825, 329131236134906506988748801, 345119115061395725472234262757377
(list; graph; listen)
|
|
|
OFFSET
|
1,2
|
|
|
COMMENT
|
The number of involutions in the group g_n D_{n+1} = G_n(operation) D_8.
|
|
REFERENCES
|
A. M. Cohen and D. E. Taylor, Title?, American Math Monthly, volume 114, Number 7, Aug-Sept 2007, pages 633-638
|
|
FORMULA
|
a(n)=2^(n^2)*8^n + Sum{k=1..n}{(1/2)^(k^2)*(1/8)^k}*2^(n^2)*8^n, n>=0 - Paolo P. Lava (ppl(AT)spl.at), Jul 30 2008
|
|
MATHEMATICA
|
a[0] = 1; a[n_] := a[n] = 2^(2*n + 1)*2*a[n - 1] + 1 Table[a[n], {n, 0, 20}]
|
|
CROSSREFS
|
Sequence in context: A086265 A077645 A046731 this_sequence A130035 A032629 A075602
Adjacent sequences: A130446 A130447 A130448 this_sequence A130450 A130451 A130452
|
|
KEYWORD
|
nonn,new
|
|
AUTHOR
|
Roger L. Bagula (rlbagulatftn(AT)yahoo.com), Aug 07 2007
|
|
|
Search completed in 0.002 seconds
|
