OFFSET
0,2
COMMENTS
The number of involutions in the group g_n D_{n+1} = G_n(operation) D_8.
LINKS
A. M. Cohen and D. E. Taylor, On a Certain Lie Algebra Defined by a Finite Group, American Math Monthly, volume 114, Number 7, Aug-Sept 2007, pages 633-638
MATHEMATICA
a[0] = 1; a[n_] := a[n] = 2^(2*n + 1)*2*a[n - 1] + 1 Table[a[n], {n, 0, 20}]
nxt[{n_, a_}]:={n+1, 4^(n+2) a+1}; NestList[nxt, {0, 1}, 10][[;; , 2]] (* Harvey P. Dale, Mar 13 2023 *)
PROG
(PARI) a(n) = if (n==0, 1, 4^(n+1)*a(n-1)+1); \\ Michel Marcus, Sep 29 2017
CROSSREFS
KEYWORD
nonn
AUTHOR
Roger L. Bagula, Aug 07 2007
EXTENSIONS
Definition and offset corrected by R. J. Mathar, Dec 05 2008
Name corrected by Michel Marcus, Sep 29 2017
STATUS
approved