A292111 Reflective-symmetric maximal chord diagrams by genus, type II.

1, 3, 25, 287, 4581, 90519, 2162901, 60249195, 1921751145, 68980179915, 2753007869745, 120897239789655, 5793717903994125, 300853185244127775, 16827530131748868525, 1008587483705141381475, 64489667984539976819025, 4381676846834476985593875, 315247855540260994097063625

Offset

1,2

Links

Table of n, a(n) for n=1..19.

Evgeniy Krasko, Counting Unlabelled Chord Diagrams of Maximal Genus, arXiv:1709.00796 [math.CO], 2017. See Table 1, column 3.

Formula

a(n) = (2*n-1) * A347951(n-1). [Krasko] - Andrei Zabolotskii, Dec 29 2025

Crossrefs

The other three sequences in Table 1 are A291172, A347951, A291371.

Sequence in context: A229162 A363354 A347255 * A393867 A123989 A390064

Adjacent sequences: A292108 A292109 A292110 * A292112 A292113 A292114

Keyword

nonn

Author

N. J. A. Sloane, Sep 20 2017

Extensions

Name clarified by Evgeniy Krasko, Sep 30 2017

a(13) onwards from Andrei Zabolotskii, Dec 30 2025

Status

approved