OFFSET
0,3
COMMENTS
Pseudo-Galois numbers for d=4; order of group AGL(n,2^2).
REFERENCES
J. H. Conway, R. T. Curtis, S. P. Norton, R. A. Parker and R. A. Wilson, ATLAS of Finite Groups. Oxford Univ. Press, 1985 [for best online version see https://oeis.org/wiki/Welcome#Links_to_Other_Sites], p. xii (but beware typos!).
LINKS
Vincenzo Librandi, Table of n, a(n) for n = 0..40
FORMULA
a(n) = p^n Product (p^n - p^k) for k=0 to n-1
MAPLE
f:=proc(n, eps) local m, d;
if n mod 2 = 0 then m:=n/2; d:=gcd(4, 2^m-eps);
2^(m*(m-1))*mul( 4^i-1, i=1..m)*(2^m-eps)/d;
else m:=(n-1)/2;
2^(m^2)*mul( 4^i-1, i=1..m);
fi; end;
[seq(f(n, +1), n=0..20)]
MATHEMATICA
FoldList[ #1*4^#2 (4^#2-1)&, 1, Range[ 20 ] ]
CROSSREFS
KEYWORD
nonn
AUTHOR
EXTENSIONS
Entry revised by N. J. A. Sloane, Dec 30 2008
STATUS
approved