Number of composable pairs (y, v) of integer compositions of n, where a composition is regarded as an arrow from the number of parts to the number of distinct parts.
A355388
Number of composable pairs (y, v) of integer compositions of n, where a composition is regarded as an arrow from the number of parts to the number of distinct parts.
Terms
- a(0) =1a(1) =1a(2) =2a(3) =6a(4) =18a(5) =58a(6) =174a(7) =536a(8) =1656a(9) =4947a(10) =14800a(11) =43157a(12) =126572a(13) =364070a(14) =1039926a(15) =2938898a(16) =8223400a(17) =22846370a(18) =62930113a(19) =172177400a(20) =467002792a(21) =1259736804a(22) =3371190792a(23) =8973530491a(24) =23728305128a(25) =62421018163a(26) =163255839779a(27) =424842462529
External references
- oeis: A355388