A336747 - cp's OEIS frontend

A336747 Number of Colombian variant Langford pairings (solutions to Langford problem such that exactly one instance of {1, 2, 3, ..., n-2, n} occurs between the two instances of n-1), up to reversal of the order.

n	a(n)
1	0
2	0
3	1
4	1
5	0
6	0
7	3
8	10
9	0
10	0
11	76
12	140
13	0
14	0
15	2478
16	5454
17	0
18	0
19	105704
20	267312
21	0
22	0
23	7235244
24	25244832
25	0
26	0
27	709868768
28	2310292004
29	0
30	0
31	91242419796
32	339602328050
33	0
34	0
35	15469115987732
36	54988746724416
37	0
38	0
39	3075508960864496
40	11965953308933012

[0, 0, 1, 1, 0, 0, 3, 10, 0, 0, 76, 140, 0, 0, 2478, 5454, 0, 0, 105704, 267312, 0, 0, 7235244, 25244832, 0, 0, 709868768, 2310292004, 0, 0, 91242419796, 339602328050, 0, 0, 15469115987732, 54988746724416, 0, 0, 3075508960864496, 11965953308933012]

cp's OEIS Frontend

A336747 Number of Colombian variant Langford pairings (solutions to Langford problem such that exactly one instance of {1, 2, 3, ..., n-2, n} occurs between the two instances of n-1), up to reversal of the order.

Table of values

List of values