a(n) is equal to the last point of a reverse pyramid summation with base 1, 2, 3, ..., n-2, n-1, n, n-1, n-2, ..., 3, 2, 1.
A359087
a(n) is equal to the last point of a reverse pyramid summation with base 1, 2, 3, ..., n-2, n-1, n, n-1, n-2, ..., 3, 2, 1.
Terms
- a(0) =1a(1) =4a(2) =19a(3) =78a(4) =301a(5) =1108a(6) =3951a(7) =13758a(8) =47049a(9) =158616a(10) =528619a(11) =1745098a(12) =5715429a(13) =18593032a(14) =60136183a(15) =193525002a(16) =620046513a(17) =1978886448a(18) =6293809971a(19) =19955385762a(20) =63094947981a(21) =198990438408a(22) =626141673375
External references
- oeis: A359087