A006444 Number of achiral 2-connected planar maps with n edges. (Formerly M0804)

0, 1, 2, 3, 6, 14, 30, 77, 196, 525, 1414, 3960, 11056, 31636, 90818, 264657, 774146, 2289787, 6798562, 20354005, 61164374, 184985060, 561433922, 1712696708, 5241637812

Offset

1,3

References

N. J. A. Sloane and Simon Plouffe, The Encyclopedia of Integer Sequences, Academic Press, 1995 (includes this sequence).

T. R. S. Walsh, personal communication.

Links

Table of n, a(n) for n=1..25.

Timothy R. Walsh, Number of sensed planar maps with n edges and m vertices, p. 44.

Crossrefs

Cf. A006402 (sensed), A006403 (unsensed), A006443 (connected), A006445 (3-connected).

Sequence in context: A106364 A211931 A264078 * A335242 A032047 A032065

Adjacent sequences: A006441 A006442 A006443 * A006445 A006446 A006447

Keyword

nonn

Author

N. J. A. Sloane

Status

approved