A281914 - cp's OEIS frontend

A281914 Number of ordered integer pairs (b,c), with -n<=b<=n, -n<=c<=n, such that both roots of 3x^2+bx+c = 0 are rational and b and are not both multiples of 3.

n	a(n)
1	2
2	8
3	8
4	16
5	24
6	24
7	34
8	46
9	46
10	60
11	72
12	74
13	86
14	100
15	104
16	122
17	132
18	132
19	142
20	164
21	168
22	182
23	192
24	200
25	214
26	228
27	228
28	250
29	260
30	268
31	278
32	300
33	304
34	318
35	336
36	340
37	350
38	364
39	368
40	398
41	408
42	416
43	426
44	448
45	452
46	466
47	476
48	488
49	502
50	524

[2, 8, 8, 16, 24, 24, 34, 46, 46, 60, 72, 74, 86, 100, 104, 122, 132, 132, 142, 164, 168, 182, 192, 200, 214, 228, 228, 250, 260, 268, 278, 300, 304, 318, 336, 340, 350, 364, 368, 398, 408, 416, 426, 448, 452, 466, 476, 488, 502, 524]

cp's OEIS Frontend

A281914 Number of ordered integer pairs (b,c), with -n<=b<=n, -n<=c<=n, such that both roots of 3x^2+bx+c = 0 are rational and b and are not both multiples of 3.

Table of values

List of values

n	a(n)
1	2
2	8
3	8
4	16
5	24
6	24
7	34
8	46
9	46
10	60
11	72
12	74
13	86
14	100
15	104
16	122
17	132
18	132
19	142
20	164
21	168
22	182
23	192
24	200
25	214
26	228
27	228
28	250
29	260
30	268
31	278
32	300
33	304
34	318
35	336
36	340
37	350
38	364
39	368
40	398
41	408
42	416
43	426
44	448
45	452
46	466
47	476
48	488
49	502
50	524

n	a(n)
1	2
2	8
3	8
4	16
5	24
6	24
7	34
8	46
9	46
10	60
11	72
12	74
13	86
14	100
15	104
16	122
17	132
18	132
19	142
20	164
21	168
22	182
23	192
24	200
25	214
26	228
27	228
28	250
29	260
30	268
31	278
32	300
33	304
34	318
35	336
36	340
37	350
38	364
39	368
40	398
41	408
42	416
43	426
44	448
45	452
46	466
47	476
48	488
49	502
50	524

n	a(n)
1	2
2	8
3	8
4	16
5	24
6	24
7	34
8	46
9	46
10	60
11	72
12	74
13	86
14	100
15	104
16	122
17	132
18	132
19	142
20	164
21	168
22	182
23	192
24	200
25	214
26	228
27	228
28	250
29	260
30	268
31	278
32	300
33	304
34	318
35	336
36	340
37	350
38	364
39	368
40	398
41	408
42	416
43	426
44	448
45	452
46	466
47	476
48	488
49	502
50	524