A131087 - OEIS

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A131087 as a triangular array

												1
											2		1
										1		4		1
									2		5		6		1
								1		8		11		8		1
							2		9		20		19		10		1
						1		12		29		40		29		12		1
					2		13		42		69		70		41		14		1
				1		16		55		112		139		112		55		16		1
			2		17		72		167		252		251		168		71		18		1
		1		20		89		240		419		504		419		240		89		20		1
	2		21		110		329		660		923		924

A131087 as a square array

1	2	1	2	1	2	1	2	1	2	1	2
1	4	5	8	9	12	13	16	17	20	21
1	6	11	20	29	42	55	72	89	110
1	8	19	40	69	112	167	240	329
1	10	29	70	139	252	419	660
1	12	41	112	251	504	923
1	14	55	168	419	924
1	16	71	240
1	18	89
1	20
1

A131087 as an upper right triangle

1	2	1	2	1	2	1	2	1	2	1	2
	1	4	5	8	9	12	13	16	17	20	21
		1	6	11	20	29	42	55	72	89	110
			1	8	19	40	69	112	167	240	329
				1	10	29	70	139	252	419	660
					1	12	41	112	251	504	923
						1	14	55	168	419	924
							1	16	71	240
								1	18	89
									1	20
										1