login
The OEIS is supported by the many generous donors to the OEIS Foundation.

 

Logo
Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A089709 a(1) = 1, a(2) = 2; for n>2, a(n) = sum_{r=1..n} {sum of all previous terms taken r at a time}. 1
1, 2, 6, 36, 360, 6480, 220320, 14541120, 1890345600, 487709164800, 250682510707200, 257200255985587200, 527260524770453760000, 2160713630509319508480000, 17704887488393364052485120000 (list; graph; refs; listen; history; text; internal format)
OFFSET
1,2
LINKS
FORMULA
a(n)=(2^(n-2)+2)*a(n-1), n>3. - Vladeta Jovovic, Nov 17 2003
EXAMPLE
a(4) = [{a(1)} + {a(2)} + {a(3)}] + [{(a(1) + a(2)} + {a(1) + a(3)} + { a(2) + a(3)}] + [{a(1) + a(2) + a(3)}] = 36.
CROSSREFS
Cf. A089985.
Sequence in context: A133822 A133892 A196870 * A262234 A371043 A055512
KEYWORD
nonn
AUTHOR
Amarnath Murthy, Nov 14 2003
EXTENSIONS
More terms from Ray Chandler, Nov 21 2003
STATUS
approved

Lookup | Welcome | Wiki | Register | Music | Plot 2 | Demos | Index | Browse | More | WebCam
Contribute new seq. or comment | Format | Style Sheet | Transforms | Superseeker | Recents
The OEIS Community | Maintained by The OEIS Foundation Inc.

License Agreements, Terms of Use, Privacy Policy. .

Last modified March 28 12:59 EDT 2024. Contains 371254 sequences. (Running on oeis4.)