A343093 Number of rooted toroidal maps with n edges and no isthmuses.

1, 14, 159, 1680, 17147, 171612, 1696491, 16631840, 162090756, 1572801142, 15210259585, 146710561296, 1412132981778, 13569013500024, 130199055578307, 1247825314752768, 11947157409479180, 114288613130155608, 1092495810452593564, 10436544808441964352

Offset

2,2

Links

Andrew Howroyd, Table of n, a(n) for n = 2..100

Formula

Conjectural g.f.: A(x) = ( Sum_{n >= 1} (1/4)*binomial(4*n, n)*x^n )^2. - Peter Bala, Jul 24 2025

Crossrefs

Row sums of A343092.

Cf. A224274, A343091.

Sequence in context: A122187 A268946 A383946 * A383783 A229611 A282043

Adjacent sequences: A343090 A343091 A343092 * A343094 A343095 A343096

Keyword

nonn

Author

Andrew Howroyd, Apr 04 2021

Status

approved