This site is supported by donations to The OEIS Foundation.

 Hints (Greetings from The On-Line Encyclopedia of Integer Sequences!)
 A092382 The O(1) loop model on the square lattice is defined as follows: At every vertex the loop turns to the left or to the right with equal probability, unless the vertex has been visited before, in which case the loop leaves the vertex via the unused edge. Every vertex is visited twice. The probability that a face of the lattice on an n X infinity cylinder is surrounded by ten loops is conjectured to be given by a(n)/A_{HT}(n)^2, where A_{HT}(n) is the number of n X n half turn symmetric alternating sign matrices. 0
 1, 1, 723668784231, 2827767747950, 1193097790725426305663064, 17520037013918467453246138, 7392624504986931437972335103490414473 (list; graph; refs; listen; history; text; internal format)
 OFFSET 20,3 REFERENCES Saibal Mitra and Bernard Nienhuis (2003), Osculating Random Walks on Cylinders, in Discrete Random Walks, DRW'03, Cyril Banderier and Christian Krattenthaler (eds.), Discrete Mathematics and Theoretical Computer Science Proceedings AC, pp. 259-264. LINKS Saibal Mitra and Bernard Nienhuis, Osculating Random Walks on Cylinders FORMULA Even n: Q(n, m)=C_{L/2-m}(n)+sum_{r=1}^{n/4-m/2}(-1)^{r}C_{n/2-m- 2r}(n)(frac{m+2r}{m+r}binom{m+r}{r}. Odd n: Q(n, m)=sum_{r=0}^{frac{(n-1)}{4}-frac{m}{2}}(-1)^{r}[C_{frac{(n-1)}{2}-m-2r}(n)-C_{frac{(n-1)}{2}-m-2r-1} (n)]binom{m+r}{r} where the c_{k}(n) are the absolute values of the coefficients of the characteristic polynomial of the n X n Pascal matrix P_{i, j}=Binom{i+j-2}{i-1}. The sequence is given by Q(n, 10) CROSSREFS Sequence in context: A105302 A015421 A180612 * A017411 A017531 A066543 Adjacent sequences:  A092379 A092380 A092381 * A092383 A092384 A092385 KEYWORD nonn AUTHOR Saibal Mitra (smitra(AT)zonnet.nl), Mar 20 2004 STATUS approved

Lookup | Welcome | Wiki | Register | Music | Plot 2 | Demos | Index | Browse | More | WebCam
Contribute new seq. or comment | Format | Transforms | Puzzles | Hot | Classics
Recent Additions | More pages | Superseeker | Maintained by The OEIS Foundation Inc.

Content is available under The OEIS End-User License Agreement .

Last modified May 20 07:10 EDT 2013. Contains 225458 sequences.