|
Search: id:A121136
|
|
|
| A121136 |
|
Numbers of isomers of unbranched a-4-catapolypentagons - see Brunvoll reference for precise definition. |
|
+0
2
|
|
| 1, 3, 13, 45, 164, 527, 1652, 4876, 14000, 38800, 105112, 278104, 722736, 1846320, 4650368, 11560320, 28413312, 69111168, 166551680, 397975680, 943672576, 2221821184, 5197313024, 12084884480, 27944656896, 64286203904, 147182565376
(list; graph; listen)
|
|
|
OFFSET
|
4,2
|
|
|
REFERENCES
|
J. Brunvoll, S. J. Cyvin and B. N. Cyvin, Isomer enumeration of polygonal systems..., J. Molec. Struct. (Theochem), 364 (1996), 1-13.
|
|
MAPLE
|
H := proc(r, alpha, q) local rhalf, alphahalf ; rhalf := floor(r/2) ; alphahalf := floor(alpha/2) ; (binomial(rhalf-1, alphahalf-1)*(q-3)+binomial(rhalf-1, alphahalf))*(q-3)^(rhalf-alphahalf-1) ; end: J := proc(r, alpha, q) (binomial(r-2, alpha-2)*(q-3)^2+2*binomial(r-2, alpha-1)*(q-3)+binomial(r-2, alpha))*(q-3)^(r-alpha-2) ; end: Ifunc := proc(r, alpha, q) J(r, alpha, q)/4+binomial(2, r-alpha)/4+ (1+(-1)^(r+alpha)+(1+(-1)^alpha)*(1-(-1)^r)/2)*H(r, alpha, q)/4 ; end: A121136 := proc(n) Ifunc(n, 4, 5) ; end: for n from 4 to 80 do printf("%d, ", A121136(n)) ; od: [From R. J. Mathar (mathar(AT)strw.leidenuniv.nl), Aug 07 2008]
|
|
CROSSREFS
|
Sequence in context: A058934 A115128 A140420 this_sequence A017943 A089930 A084519
Adjacent sequences: A121133 A121134 A121135 this_sequence A121137 A121138 A121139
Cf. A121133. [From R. J. Mathar (mathar(AT)strw.leidenuniv.nl), Aug 07 2008]
|
|
KEYWORD
|
nonn,new
|
|
AUTHOR
|
njas, Aug 13 2006
|
|
EXTENSIONS
|
Extended beyond a(10) by R. J. Mathar (mathar(AT)strw.leidenuniv.nl), Aug 07 2008
|
|
|
Search completed in 0.002 seconds
|
