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A170948 Number of twins with n edges. 1
0, 0, 0, 11, 226, 3597, 55006, 892791, 15763270, 305360481, 6483720916, 150200835113, 3774756521566, 102339496556342, 2977913930684928, 92579209306356230, 3062597993515937128, 107418845568842941190 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,4

REFERENCES

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.

LINKS

Table of n, a(n) for n=1..18.

CROSSREFS

Sequence in context: A294388 A281257 A187646 * A245076 A120850 A289716

Adjacent sequences:  A170945 A170946 A170947 * A170949 A170950 A170951

KEYWORD

nonn

AUTHOR

N. J. A. Sloane, Feb 21 2010

STATUS

approved

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Last modified October 16 13:29 EDT 2019. Contains 328091 sequences. (Running on oeis4.)