The OEIS is supported by the many generous donors to the OEIS Foundation.
%I #22 Apr 14 2026 08:40:32
%S 0,1,2,4,13,38,98,337,1062,2974,10468,34120,99658,355369,1181126,
%T 3540464,12731141,42860534,130771376,473018396,1607076200,4967127736,
%U 18045744424,61732449648,192696614730,702457703961,2415935640198,7600482116932,27782297425063
%N Number of pinnacle sets in the n-antiprism graph.
%C Sequence extended to a(0)-a(2) using the formula.
%H Eric Weisstein's World of Mathematics, <a href="https://mathworld.wolfram.com/AntiprismGraph.html">Antiprism Graph</a>.
%H Eric Weisstein's World of Mathematics, <a href="https://mathworld.wolfram.com/PinnacleSet.html">Pinnacle Set</a>.
%F a(n) = A126042(2*n-3).
%t Table[Sum[(2 n - 3 k + 1) Binomial[2 n - 3, k - 1]/(2 n - k - 1), {k, Floor[2 n/3]}], {n, 20}]
%K nonn
%O 1,3
%A _Eric W. Weisstein_, Apr 06 2026