A072732 - cp's OEIS frontend

A072732 Simple triangle-stretching N X N -> N bijection: push terms in the middle twice as far down to make space for the terms obtained by bisecting the edges, which are thus contracted by the same factor. Do this for all "triangle-shells" successively contained inside each other in A001477.

n	a(n)
0	0
1	1
2	4
3	7
4	12
5	2
6	3
7	17
8	24
9	8
10	11
11	31
12	40
13	18
14	5
15	6
16	23
17	49
18	60
19	32
20	13
21	16
22	39
23	71
24	84
25	50
26	25
27	9
28	10
29	30
30	59
31	97
32	112
33	72
34	41
35	19
36	22
37	48
38	83
39	127
40	144
41	98
42	61
43	33
44	14
45	15
46	38
47	70
48	111
49	161
50	180
51	128
52	85
53	51
54	26
55	29
56	58
57	96
58	143
59	199
60	220
61	162
62	113
63	73
64	42
65	20
66	21
67	47

[0, 1, 4, 7, 12, 2, 3, 17, 24, 8, 11, 31, 40, 18, 5, 6, 23, 49, 60, 32, 13, 16, 39, 71, 84, 50, 25, 9, 10, 30, 59, 97, 112, 72, 41, 19, 22, 48, 83, 127, 144, 98, 61, 33, 14, 15, 38, 70, 111, 161, 180, 128, 85, 51, 26, 29, 58, 96, 143, 199, 220, 162, 113, 73, 42, 20, 21, 47]

cp's OEIS Frontend

A072732 Simple triangle-stretching N X N -> N bijection: push terms in the middle twice as far down to make space for the terms obtained by bisecting the edges, which are thus contracted by the same factor. Do this for all "triangle-shells" successively contained inside each other in A001477.

Table of values

List of values

n	a(n)
0	0
1	1
2	4
3	7
4	12
5	2
6	3
7	17
8	24
9	8
10	11
11	31
12	40
13	18
14	5
15	6
16	23
17	49
18	60
19	32
20	13
21	16
22	39
23	71
24	84
25	50
26	25
27	9
28	10
29	30
30	59
31	97
32	112
33	72
34	41
35	19
36	22
37	48
38	83
39	127
40	144
41	98
42	61
43	33
44	14
45	15
46	38
47	70
48	111
49	161
50	180
51	128
52	85
53	51
54	26
55	29
56	58
57	96
58	143
59	199
60	220
61	162
62	113
63	73
64	42
65	20
66	21
67	47

n	a(n)
0	0
1	1
2	4
3	7
4	12
5	2
6	3
7	17
8	24
9	8
10	11
11	31
12	40
13	18
14	5
15	6
16	23
17	49
18	60
19	32
20	13
21	16
22	39
23	71
24	84
25	50
26	25
27	9
28	10
29	30
30	59
31	97
32	112
33	72
34	41
35	19
36	22
37	48
38	83
39	127
40	144
41	98
42	61
43	33
44	14
45	15
46	38
47	70
48	111
49	161
50	180
51	128
52	85
53	51
54	26
55	29
56	58
57	96
58	143
59	199
60	220
61	162
62	113
63	73
64	42
65	20
66	21
67	47

n	a(n)
0	0
1	1
2	4
3	7
4	12
5	2
6	3
7	17
8	24
9	8
10	11
11	31
12	40
13	18
14	5
15	6
16	23
17	49
18	60
19	32
20	13
21	16
22	39
23	71
24	84
25	50
26	25
27	9
28	10
29	30
30	59
31	97
32	112
33	72
34	41
35	19
36	22
37	48
38	83
39	127
40	144
41	98
42	61
43	33
44	14
45	15
46	38
47	70
48	111
49	161
50	180
51	128
52	85
53	51
54	26
55	29
56	58
57	96
58	143
59	199
60	220
61	162
62	113
63	73
64	42
65	20
66	21
67	47