A381192 - cp's OEIS frontend

A381192 Irregular triangle read by rows. Properly color the vertices of a simple labeled graph on [n] using exactly n colors c_1 (in other words, use each color exactly once). Orient the edges according to the strict order on the colors. T(n,k) is the number of such graphs with exactly k descents, n>=0, 0<=k<=binomial(n,2).

n	a(n)
0	1
1	1
2	3
3	1
4	21
5	19
6	7
7	1
8	315
9	516
10	419
11	208
12	65
13	12
14	1
15	9765
16	24186
17	31445
18	27488
19	17538
20	8420
21	3050
22	816
23	153
24	18
25	1
26	615195
27	2080323
28	3769767
29	4754751
30	4592847
31	3555479
32	2257723
33	1188595
34	519745
35	187705
36	55237
37	12941
38	2325
39	301
40	25
41	1

[1, 1, 3, 1, 21, 19, 7, 1, 315, 516, 419, 208, 65, 12, 1, 9765, 24186, 31445, 27488, 17538, 8420, 3050, 816, 153, 18, 1, 615195, 2080323, 3769767, 4754751, 4592847, 3555479, 2257723, 1188595, 519745, 187705, 55237, 12941, 2325, 301, 25, 1]

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