A359087 - cp's OEIS frontend

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.

n	a(n)
1	1
2	4
3	19
4	78
5	301
6	1108
7	3951
8	13758
9	47049
10	158616
11	528619
12	1745098
13	5715429
14	18593032
15	60136183
16	193525002
17	620046513
18	1978886448
19	6293809971
20	19955385762
21	63094947981
22	198990438408
23	626141673375
24	1966085927898
25	6161660863929
26	19276374528468
27	60206635741131

[1, 4, 19, 78, 301, 1108, 3951, 13758, 47049, 158616, 528619, 1745098, 5715429, 18593032, 60136183, 193525002, 620046513, 1978886448, 6293809971, 19955385762, 63094947981, 198990438408, 626141673375, 1966085927898, 6161660863929, 19276374528468, 60206635741131]

cp's OEIS Frontend

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.

Table of values

List of values