A387567 Number of matchings in the n-Lindgren-Sousselier graph.

332, 12210, 411402, 13182776, 408531656, 12362010796, 367445471844, 10771214079422, 312257159548526, 8970446710113232, 255757149683012884, 7245354262258139600, 204130142194772860028, 5723850754694267780426, 159831156397794486754386, 4446714843514546755378536

Offset

1,1

Links

Andrew Howroyd, Table of n, a(n) for n = 1..200

Eric Weisstein's World of Mathematics, Independent Edge Set.

Eric Weisstein's World of Mathematics, Lindgren-Sousselier Graphs.

Index entries for linear recurrences with constant coefficients, signature (50,-561,-1582,-1476,-526,-17,18,-1).

Formula

G.f.: 2*x*(166 - 2195*x - 6423*x^2 - 6145*x^3 - 2185*x^4 - 56*x^5 + 74*x^6 - 4*x^7)/(1 - 25*x - 32*x^2 - 9*x^3 + x^4)^2. - Andrew Howroyd, Jan 17 2026

Crossrefs

Sequence in context: A114084 A257892 A235020 * A111690 A095199 A158081

Adjacent sequences: A387564 A387565 A387566 * A387568 A387569 A387570

Keyword

nonn,easy

Author

Eric W. Weisstein, Sep 02 2025

Extensions

a(12) onward from Andrew Howroyd, Jan 17 2026

Status

approved