A270309 - cp's OEIS frontend

A270309 Irregular triangle read by rows: T(n,k) = ((n-k)+1)^2 if odd-n and odd-k; T(n,k) = k^2 if odd-n and even-k; T(n,k) = (n/2-(k/2-1/2))^2 if even-n and odd-k; T(n,k) = (k/2+1)^2 if even-n and even-k; where n >= 1, k = 1..2*n.

n	a(n)
1	1
2	1
3	1
4	1
5	1
6	1
7	9
8	4
9	1
10	1
11	4
12	9
13	4
14	1
15	1
16	4
17	4
18	1
19	1
20	4
21	25
22	4
23	9
24	16
25	1
26	1
27	16
28	9
29	4
30	25
31	9
32	1
33	4
34	4
35	1
36	9
37	9
38	1
39	4
40	4
41	1
42	9
43	49
44	4
45	25
46	16
47	9
48	36
49	1
50	1
51	36
52	9
53	16
54	25
55	4
56	49
57	16
58	1
59	9
60	4
61	4
62	9
63	1
64	16
65	16
66	1
67	9
68	4
69	4
70	9
71	1
72	16
73	81
74	4
75	49
76	16
77	25
78	36
79	9
80	64
81	1
82	1
83	64
84	9
85	36
86	25
87	16
88	49
89	4
90	81
91	25
92	1
93	16
94	4
95	9
96	9
97	4
98	16
99	1
100	25
101	25
102	1
103	16
104	4
105	9
106	9
107	4
108	16
109	1
110	25

[1, 1, 1, 1, 1, 1, 9, 4, 1, 1, 4, 9, 4, 1, 1, 4, 4, 1, 1, 4, 25, 4, 9, 16, 1, 1, 16, 9, 4, 25, 9, 1, 4, 4, 1, 9, 9, 1, 4, 4, 1, 9, 49, 4, 25, 16, 9, 36, 1, 1, 36, 9, 16, 25, 4, 49, 16, 1, 9, 4, 4, 9, 1, 16, 16, 1, 9, 4, 4, 9, 1, 16, 81, 4, 49, 16, 25, 36, 9, 64, 1, 1, 64, 9, 36, 25, 16, 49, 4, 81, 25, 1, 16, 4, 9, 9, 4, 16, 1, 25, 25, 1, 16, 4, 9, 9, 4, 16, 1, 25]

cp's OEIS Frontend

A270309 Irregular triangle read by rows: T(n,k) = ((n-k)+1)^2 if odd-n and odd-k; T(n,k) = k^2 if odd-n and even-k; T(n,k) = (n/2-(k/2-1/2))^2 if even-n and odd-k; T(n,k) = (k/2+1)^2 if even-n and even-k; where n >= 1, k = 1..2*n.

Table of values

List of values

n	a(n)
1	1
2	1
3	1
4	1
5	1
6	1
7	9
8	4
9	1
10	1
11	4
12	9
13	4
14	1
15	1
16	4
17	4
18	1
19	1
20	4
21	25
22	4
23	9
24	16
25	1
26	1
27	16
28	9
29	4
30	25
31	9
32	1
33	4
34	4
35	1
36	9
37	9
38	1
39	4
40	4
41	1
42	9
43	49
44	4
45	25
46	16
47	9
48	36
49	1
50	1
51	36
52	9
53	16
54	25
55	4
56	49
57	16
58	1
59	9
60	4
61	4
62	9
63	1
64	16
65	16
66	1
67	9
68	4
69	4
70	9
71	1
72	16
73	81
74	4
75	49
76	16
77	25
78	36
79	9
80	64
81	1
82	1
83	64
84	9
85	36
86	25
87	16
88	49
89	4
90	81
91	25
92	1
93	16
94	4
95	9
96	9
97	4
98	16
99	1
100	25
101	25
102	1
103	16
104	4
105	9
106	9
107	4
108	16
109	1
110	25

n	a(n)
1	1
2	1
3	1
4	1
5	1
6	1
7	9
8	4
9	1
10	1
11	4
12	9
13	4
14	1
15	1
16	4
17	4
18	1
19	1
20	4
21	25
22	4
23	9
24	16
25	1
26	1
27	16
28	9
29	4
30	25
31	9
32	1
33	4
34	4
35	1
36	9
37	9
38	1
39	4
40	4
41	1
42	9
43	49
44	4
45	25
46	16
47	9
48	36
49	1
50	1
51	36
52	9
53	16
54	25
55	4
56	49
57	16
58	1
59	9
60	4
61	4
62	9
63	1
64	16
65	16
66	1
67	9
68	4
69	4
70	9
71	1
72	16
73	81
74	4
75	49
76	16
77	25
78	36
79	9
80	64
81	1
82	1
83	64
84	9
85	36
86	25
87	16
88	49
89	4
90	81
91	25
92	1
93	16
94	4
95	9
96	9
97	4
98	16
99	1
100	25
101	25
102	1
103	16
104	4
105	9
106	9
107	4
108	16
109	1
110	25

n	a(n)
1	1
2	1
3	1
4	1
5	1
6	1
7	9
8	4
9	1
10	1
11	4
12	9
13	4
14	1
15	1
16	4
17	4
18	1
19	1
20	4
21	25
22	4
23	9
24	16
25	1
26	1
27	16
28	9
29	4
30	25
31	9
32	1
33	4
34	4
35	1
36	9
37	9
38	1
39	4
40	4
41	1
42	9
43	49
44	4
45	25
46	16
47	9
48	36
49	1
50	1
51	36
52	9
53	16
54	25
55	4
56	49
57	16
58	1
59	9
60	4
61	4
62	9
63	1
64	16
65	16
66	1
67	9
68	4
69	4
70	9
71	1
72	16
73	81
74	4
75	49
76	16
77	25
78	36
79	9
80	64
81	1
82	1
83	64
84	9
85	36
86	25
87	16
88	49
89	4
90	81
91	25
92	1
93	16
94	4
95	9
96	9
97	4
98	16
99	1
100	25
101	25
102	1
103	16
104	4
105	9
106	9
107	4
108	16
109	1
110	25