A039660 Related to enumeration of edge-rooted catafusenes.

0, 0, 0, 1, 2, 8, 14, 43, 72, 204, 336, 926, 1516, 4144, 6772, 18504, 30236, 82844, 135452, 372581, 609710, 1684220, 2758730, 7652531, 12546332, 34941752, 57337172, 160280987, 263224802, 738363872, 1213502942, 3414804517

Offset

1,5

Comments

Let b(n>=0) = 0, 0, 0, 0, 1, 0, 6, 0, 29, 0, 132, 0, 590, 0, 2628, ... be the

"aerated" version of A045445. This sequence is the convolution of A040000 and b. - R. J. Mathar, Jul 30 2019

Links

Table of n, a(n) for n=1..32.

S. J. Cyvin et al., Enumeration and classification of benzenoid systems. 32. Normal perifusenes with two internal vertices, J. Chem. Inform. Comput. Sci., 32 (1992), 532-540.

Formula

G.f.: (1+x)[1-6x^2+7x^4-(1-3x^2)sqrt(1-6x^2+5x^4)]/[2x^4(1-x)] (eq. (11) in Cyvin et al.)

Crossrefs

Sequence in context: A162484 A333575 A259119 * A333053 A333054 A119752

Adjacent sequences: A039657 A039658 A039659 * A039661 A039662 A039663

Keyword

nonn

Author

N. J. A. Sloane.

Extensions

More terms from Emeric Deutsch, Mar 14 2004

Status

approved