id:A138180 - OEIS Search Results

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Irregular triangle read by rows: row n consists of all numbers x such that x and x+1 are both prime(n)-smooth numbers.

+0
3

1, 1, 2, 3, 8, 1, 2, 3, 4, 5, 8, 9, 15, 24, 80, 1, 2, 3, 4, 5, 6, 7, 8, 9, 14, 15, 20, 24, 27, 35, 48, 49, 63, 80, 125, 224, 2400, 4374, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 14, 15, 20, 21, 24, 27, 32, 35, 44, 48, 49, 54, 55, 63, 80, 98, 99, 120, 125, 175, 224, 242, 384, 440, 539 (list; graph; listen)

	OFFSET	`1,3`
	COMMENT	`A number x is p-smooth if all prime factors of x are <= p. The length of row n is A002071(n). Row n begins with 1 and ends with A002072(n). Each term of row n-1 is in row n.`
	REFERENCES	`See A002071.`
	LINKS	`T. D. Noe, Rows n=1..10 of triangle, flattened`
	CROSSREFS	`Cf. A085152, A085153.` `Sequence in context: A088332 A131959 A021046 this_sequence A079585 A058485 A011326` `Adjacent sequences: A138177 A138178 A138179 this_sequence A138181 A138182 A138183`
	KEYWORD	`nonn`
	AUTHOR	`T. D. Noe (noe(AT)sspectra.com), Mar 04 2008`

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Last modified November 25 08:46 EST 2009. Contains 167481 sequences.

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