This site is supported by donations to The OEIS Foundation.

 Hints (Greetings from The On-Line Encyclopedia of Integer Sequences!)
 A006629 Self-convolution 4th power of A001764, which enumerates ternary trees. (Formerly M3542) 22
 1, 4, 18, 88, 455, 2448, 13566, 76912, 444015, 2601300, 15426840, 92431584, 558685348, 3402497504, 20858916870, 128618832864, 797168807855, 4963511449260, 31032552351570, 194743066471800, 1226232861415695 (list; graph; refs; listen; history; text; internal format)
 OFFSET 0,2 COMMENTS Sum of root degrees of all noncrossing trees on nodes on a circle. - Emeric Deutsch REFERENCES H. M. Finucan, Some decompositions of generalized Catalan numbers, pp. 275-293 of Combinatorial Mathematics IX. Proc. Ninth Australian Conference (Brisbane, August 1981). Ed. E. J. Billington, S. Oates-Williams and A. P. Street. Lecture Notes Math., 952. Springer-Verlag, 1982. N. J. A. Sloane and Simon Plouffe, The Encyclopedia of Integer Sequences, Academic Press, 1995 (includes this sequence). LINKS Andrew Howroyd, Table of n, a(n) for n = 0..200 Emanuele Munarini, Shifting Property for Riordan, Sheffer and Connection Constants Matrices, Journal of Integer Sequences, Vol. 20 (2017), Article 17.8.2. C. H. Pah, Single polygon counting on Cayley Tree of order 3, J. Stat. Phys. 140 (2010) 198-207 FORMULA a(n) = 2*binomial(3*n+3,n)/(n+2). - Emeric Deutsch G.f.: 3_F_2 ( [ 2, 5/3, 4/3 ]; [ 3, 5/2 ]; 27 x / 4 ). G.f.: A(x) = G(x)^4 where G(x) = 1 + x*G(x)^3 = g.f. of A001764 giving a(n)=C(3n+m-1,n)*m/(2n+m) at power m=4 with offset n=0. - Paul D. Hanna, May 10 2008 PROG (PARI) a(n)=my(m=4); binomial(3*n+m-1, n)*m/(2*n+m) /* 4th power of A001764 with offset n=0 */ \\ Paul D. Hanna, May 10 2008 CROSSREFS Column 2 of A092276. Sequence in context: A081671 A244785 A260650 * A068764 A127394 A046984 Adjacent sequences:  A006626 A006627 A006628 * A006630 A006631 A006632 KEYWORD nonn,easy AUTHOR EXTENSIONS More precise definition from Paul D. Hanna, May 10 2008 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.

Last modified September 18 09:56 EDT 2019. Contains 327169 sequences. (Running on oeis4.)