Number of foldings of n labeled stamps in which leaf 1 is inwards and leaf n outwards (or leaf 1 outwards and leaf n inwards).
A223093
Number of foldings of n labeled stamps in which leaf 1 is inwards and leaf n outwards (or leaf 1 outwards and leaf n inwards).
Terms
- a(0) =0a(1) =0a(2) =2a(3) =4a(4) =16a(5) =38a(6) =132a(7) =342a(8) =1144a(9) =3134a(10) =10370a(11) =29526a(12) =97458a(13) =285458a(14) =942920a(15) =2822310a(16) =9341008a(17) =28440970a(18) =94358558a(19) =291294678a(20) =968853072a(21) =3025232480a(22) =10086634316a(23) =31797822936a(24) =106265437078a(25) =337731551446
External references
- oeis: A223093