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A128055 a(n) = 2^A128054(n). 4
1, 1, 2, 4, 8, 32, 64, 64, 128, 256, 512, 2048, 4096, 4096, 8192, 16384, 32768, 131072, 262144, 262144, 524288, 1048576, 2097152, 8388608, 16777216, 16777216, 33554432, 67108864, 134217728, 536870912, 1073741824 (list; graph; refs; listen; history; text; internal format)
OFFSET
0,3
COMMENTS
A factor in A128056.
The signed sequence 1,1,2,-4,-8,-32,-64,-64,-128,256,512... is the Hankel transform of the doubled sequence 1,1,2,2,6,6,... of central binomial coefficients (A128014). - Paul Barry, Sep 09 2008
LINKS
FORMULA
G.f.: (-1-16*x^4+4*x^3-4*x^2+x)/((2*x-1)*(4*x^2-2*x+1)*(4*x^2+2*x+1)). - Maksym Voznyy (voznyy(AT)mail.ru), Aug 11 2009
Sum_{n>=0} 1/a(n) = 62/21. - Amiram Eldar, Mar 28 2023
CROSSREFS
Sequence in context: A151406 A307611 A053147 * A061285 A194810 A271216
KEYWORD
easy,nonn
AUTHOR
Paul Barry, Feb 13 2007
STATUS
approved

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Last modified June 20 05:29 EDT 2024. Contains 373512 sequences. (Running on oeis4.)