|
Search: id:A066532
|
|
|
| A066532 |
|
If n is odd a(n) = 1, if n is even a(n) = 2^(n-1). |
|
+0
1
|
|
| 1, 2, 1, 8, 1, 32, 1, 128, 1, 512, 1, 2048, 1, 8192, 1, 32768, 1, 131072, 1, 524288, 1, 2097152, 1, 8388608, 1, 33554432, 1, 134217728, 1, 536870912, 1, 2147483648, 1, 8589934592, 1, 34359738368, 1, 137438953472, 1, 549755813888, 1
(list; graph; listen)
|
|
|
OFFSET
|
1,2
|
|
|
COMMENT
|
Size of Frattini subgroup of the group of n X n signed permutations matrices (described in sequence A066051).
|
|
FORMULA
|
G.f.: G.f.: 1/(1-x^2)+2x(1+2x^2)/(1-2x^2); a(n)=2^n*(1-(-1)^n)/2+(1+(-1)^n)/2. - Paul Barry (pbarry(AT)wit.ie), Jun 17 2006
|
|
MATHEMATICA
|
Table[ If[ OddQ[n], 1, 2^(n - 1)], {n, 1, 42} ]
|
|
CROSSREFS
|
Cf. A066051.
Sequence in context: A101280 A008309 A131175 this_sequence A020778 A118961 A114706
Adjacent sequences: A066529 A066530 A066531 this_sequence A066533 A066534 A066535
|
|
KEYWORD
|
nonn,easy
|
|
AUTHOR
|
Sharon Sela (sharonsela(AT)hotmail.com), Jan 06 2002
|
|
EXTENSIONS
|
More terms from Robert G. Wilson v (rgwv(AT)rgwv.com), Jan 07 2002
More terms from Ralf Stephan (ralf(AT)ark.in-berlin.de), Jul 25 2003
|
|
|
Search completed in 0.005 seconds
|
