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

 

Logo

Year-end appeal: Please make a donation to the OEIS Foundation to support ongoing development and maintenance of the OEIS. We are now in our 56th year, we are closing in on 350,000 sequences, and we’ve crossed 9,700 citations (which often say “discovered thanks to the OEIS”).

Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A076261 Triangle T(n,k) (n >= 2, 1 <= k <= n-1) read by rows, where T(n,k) is the number of words of length n in the free group on two generators that require exactly k multiplications for their formation. 1
4, 0, 8, 0, 4, 12, 0, 0, 18, 14, 0, 0, 10, 44, 10, 0, 0, 0, 50, 74, 4 (list; table; graph; refs; listen; history; text; internal format)
OFFSET

2,1

LINKS

Table of n, a(n) for n=2..22.

EXAMPLE

T(4,2)=4 because we can generate each of aaaa,abab,baba,bbbb with just two multiplications: e.g. ab=a*b, abab=ab*ab.

CROSSREFS

Cf. A076262.

Sequence in context: A340424 A222609 A247848 * A070802 A114401 A304440

Adjacent sequences:  A076258 A076259 A076260 * A076262 A076263 A076264

KEYWORD

more,nonn,tabl

AUTHOR

Colin Mallows, Oct 03 2002

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 November 30 20:17 EST 2021. Contains 349425 sequences. (Running on oeis4.)