login
The OEIS Foundation is supported by donations from users of the OEIS and by a grant from the Simons Foundation.

 

Logo


Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A198759 The number of pairs of braces to note the properly nested set with n elements. 1
1, 2, 4, 7, 11, 15, 20, 25, 30, 36, 42, 48, 54, 60, 66, 73, 80, 87, 94, 101, 108, 115, 122, 129, 136, 143, 150, 158, 166, 174, 182, 190, 198, 206, 214, 222, 230, 238, 246, 254, 262, 270, 278, 286, 294, 302, 310, 318, 326, 334, 342 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,2

LINKS

Table of n, a(n) for n=0..50.

F. T. Adams-Watters, Re: Set of sets using minimal number of braces, SeqFan Oct 29 2011

J. Zucker, Set of sets using minimal number of braces, SeqFan Oct 25 2011

MAPLE

# implementing the Adams-Watters partial sum formula up to nmax elements

read("transforms") ;

nmax := 40 ;

a004111rep := [1, 1] ;

n := 2 ;

while nops(a004111rep) < nmax do

        a004111rep := [op(a004111rep), seq(n, i=1..A004111(n))] ;

        n := n+1 ;

end do:

PSUM(a004111rep) ;

CROSSREFS

Cf. A004111.

Sequence in context: A250621 A003068 A194168 * A078617 A199085 A247184

Adjacent sequences:  A198756 A198757 A198758 * A198760 A198761 A198762

KEYWORD

nonn

AUTHOR

R. J. Mathar, Oct 29 2011

STATUS

approved

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

License Agreements, Terms of Use, Privacy Policy. .

Last modified May 30 18:38 EDT 2020. Contains 334728 sequences. (Running on oeis4.)