id:A081994 - OEIS Search Results

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A081994

Triangle read by rows in which the n-th row contains n numbers not occurring earlier such that every entry is coprime to all the members of the row and column it belongs.

+0
4

1, 2, 3, 5, 4, 7, 9, 11, 8, 13, 17, 19, 15, 14, 23, 29, 25, 31, 27, 16, 37, 41, 43, 47, 53, 21, 10, 59, 49, 61, 67, 55, 71, 39, 32, 73, 79, 83, 89, 97, 65, 77, 51, 38, 101, 103, 91, 107, 109, 113, 127, 95, 33, 34, 131, 121, 137, 139, 149, 151, 157, 161, 85, 57, 26, 163, 167 (list; table; graph; listen)

	OFFSET	`1,2`
	COMMENT	`Observation: The second leading diagonal contains even numbers and all other diagonals mandatorily contain odd numbers. (Proof?)`
	EXAMPLE	`Triangle begins:` `1` `2 3` `5 4 7` `9 11 8 13` `17 19 23 6 25` `...`
	CROSSREFS	`Cf. A081995, A081996, A081997.` `Sequence in context: A102399 A118318 A084937 this_sequence A090252 A140140 A119474` `Adjacent sequences: A081991 A081992 A081993 this_sequence A081995 A081996 A081997`
	KEYWORD	`tabl,nonn`
	AUTHOR	`Amarnath Murthy (amarnath_murthy(AT)yahoo.com), Apr 05 2003`
	EXTENSIONS	`Corrected and extended by Antonio G. Astudillo (afg_astudillo(AT)lycos.com), Apr 29 2003`

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Last modified November 29 12:46 EST 2009. Contains 167659 sequences.

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