Number of free pure symmetric identity multifunctions (with empty expressions allowed) with one atom and n positions.

A317876

Number of free pure symmetric identity multifunctions (with empty expressions allowed) with one atom and n positions.

Terms

    a(0) =1a(1) =1a(2) =2a(3) =4a(4) =10a(5) =25a(6) =67a(7) =184a(8) =519a(9) =1489a(10) =4342a(11) =12812a(12) =38207a(13) =114934a(14) =348397a(15) =1063050a(16) =3262588a(17) =10064645a(18) =31190985a(19) =97061431a(20) =303165207a(21) =950115502a(22) =2986817742a(23) =9415920424a(24) =29760442192a(25) =94286758293a(26) =299377379027a(27) =952521579944

External references