|
Search: id:A122746
|
|
|
| A122746 |
|
G.f.: 1/((1-2*x)*(1-2*x^2)). |
|
+0
6
|
|
| 1, 2, 6, 12, 28, 56, 120, 240, 496, 992, 2016, 4032, 8128, 16256, 32640, 65280, 130816, 261632, 523776, 1047552, 2096128, 4192256, 8386560, 16773120, 33550336, 67100672, 134209536, 268419072, 536854528, 1073709056, 2147450880, 4294901760, 8589869056
(list; graph; listen)
|
|
|
OFFSET
|
0,2
|
|
|
COMMENT
|
Equals row sums of triangle A156665 [From Gary W. Adamson (qntmpkt(AT)yahoo.com), Feb 12 2009]
a(n) is the number of subsets of {1,2,...,n+1} that contain at least one odd integer. [From Geoffrey Critzer (critzer.geoffrey(AT)usd443.org), Mar 03 2009]
|
|
REFERENCES
|
S. J. Cyvin et al., Theory of polypentagons, J. Chem. Inf. Comput. Sci., 33 (1993), 466-474.
|
|
LINKS
|
Index entries for sequences related to linear recurrences with constant coefficients
|
|
FORMULA
|
a(2k) = A006516(k+1) = 2^k*(2^(k+1) - 1) = A020522(k+1) /2. a(2k+1) = 2*A006516(k+1) = 2^(k+1)*(2^(k+1) - 1) = A020522(k+1). - Alexander Adamchuk (alex(AT)kolmogorov.com), Sep 25 2006
a(n)=2^(n+1)-2^(floor[(n+1)/2]) [From Geoffrey Critzer (critzer.geoffrey(AT)usd443.org), Mar 03 2009]
|
|
CROSSREFS
|
Essentially the same as A032085.
Cf. A006516, A020522.
A156665 [From Gary W. Adamson (qntmpkt(AT)yahoo.com), Feb 12 2009]
Sequence in context: A011949 A089820 A141447 this_sequence A057582 A094779 A093387
Adjacent sequences: A122743 A122744 A122745 this_sequence A122747 A122748 A122749
|
|
KEYWORD
|
nonn
|
|
AUTHOR
|
N. J. A. Sloane (njas(AT)research.att.com), Sep 24 2006
|
|
|
Search completed in 0.002 seconds
|
