A211990 - OEIS

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A211990 as a triangular array

												1
											1		2
										1		2		3
									2		3		4		5
								2		4		5		6		7
							4		6		8		9		10		11
						4		8		10		12		13		14		15
					7		11		15		17		19		20		21		22
				8		15		19		23		25		27		28		29		30
			12		20		27		31		35		37		39		40		41		42
		14		26		34		41		45		49		51		53		54		55		56
	21		35		47

A211990 as a square array

1	1	1	2	2	4	4	7	8	12	14	21
2	2	3	4	6	8	11	15	20	26	35
3	4	5	8	10	15	19	27	34	47
5	6	9	12	17	23	31	41
7	10	13	19	25	35	45
11	14	20	27	37	49
15	21	28	39	51
22	29	40	53
30	41	54
42	55
56

A211990 as an upper right triangle

1	1	1	2	2	4	4	7	8	12	14	21
	2	2	3	4	6	8	11	15	20	26	35
		3	4	5	8	10	15	19	27	34	47
			5	6	9	12	17	23	31	41
				7	10	13	19	25	35	45
					11	14	20	27	37	49
						15	21	28	39	51
							22	29	40	53
								30	41	54
									42	55
										56