A170947 Number of achiral combinatorial maps with n edges.

2, 5, 20, 85, 418, 2242, 12828, 77777, 493286, 3260485, 22314484, 157735801, 1147285362, 8570960234, 65611620808, 513963377327, 4113363020482, 33598074760393, 279764563749076, 2372822051513583, 20481425601917742, 179795508212739402, 1604084463778300348, 14536376462636666141

Offset: 1

Author

N. J. A. Sloane, Feb 21 2010

Keywords

• nonn

Comments

Achiral maps are also called reflexible.

Links

• Antonio Breda d'Azevedo, Alexander Mednykh, and Roman Nedela, Table of n, a(n) for n = 1..30
• Antonio Breda d'Azevedo, Alexander Mednykh, and Roman Nedela, Enumeration of maps regardless of genus: Geometric approach, Discrete Mathematics, Volume 310, 2010, Pages 1184-1203.

Crossrefs

Row sums of A380234.

Cf. A170946 (sensed), A170948 (chiral pairs), A214816 (unsensed).