A030534 Number of polyhexes of class PF2.

1, 2, 10, 40, 185, 828, 3805, 17411, 80177, 369675, 1710173, 7931011, 36884730, 171987194, 804027444, 3767994408, 17699839325, 83328339997, 393123808821, 1858351499207, 8801160980038, 41756069328689, 198437460900302, 944521149228740, 4502419787519360

Offset

4,2

Comments

See reference for precise definition.

Cyvin has incorrect a(13)=369639 and a(14)=1710137 in Table III due to using incorrect values for A026298(13) and A026298(14) in Table II. - Sean A. Irvine, Apr 02 2020

Links

Table of n, a(n) for n=4..28.

S. J. Cyvin, Zhang Fuji, B. N. Cyvin, Guo Xiaofeng, and J. Brunvoll, Enumeration and classification of benzenoid systems. 32. Normal perifusenes with two internal vertices, J. Chem. Inform. Comput. Sci., 32 (1992), 532-540.

Formula

a(4)=1, a(n) = A026106(n) + A026118(n) + A026298(n) + A030519(n) for n > 4. - Sean A. Irvine, Apr 02 2020

Crossrefs

Cf. A026106, A026118, A026298, A030519, A030520, A030525, A030529, A030532, A030534.

Sequence in context: A151024 A151025 A333799 * A335601 A151026 A151027

Adjacent sequences: A030531 A030532 A030533 * A030535 A030536 A030537

Keyword

nonn

Author

N. J. A. Sloane

Extensions

a(13) and a(14) corrected and more terms from Sean A. Irvine, Apr 02 2020

Status

approved