id:A108278 - OEIS Search Results

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Numbers n such that n^2-1 and n^2+1 are semiprimes.

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12, 30, 42, 60, 102, 108, 198, 312, 462, 522, 600, 810, 828, 1020, 1050, 1062, 1278, 1452, 1488, 1872, 1950, 2028, 2130, 2142, 2340, 2790, 2802, 2970, 3000, 3120, 3252, 3300, 3330, 3672, 3930, 4020, 4092, 4230, 4548, 4800, 5280, 5640, 5652, 5658, 6198 (list; graph; listen)

	OFFSET	`1,1`
	EXAMPLE	`a(1)=12 because 12^2-1=143=1113 and 12^2+1=145=529 are both semiprimes.`
	CROSSREFS	`Cf. A001358 semiprimes, A069062 n^2-1 and n^2+1 have the same number of divisors.` `Sequence in context: A024364 A093507 A145470 this_sequence A135502 A125582 A031107` `Adjacent sequences: A108275 A108276 A108277 this_sequence A108279 A108280 A108281`
	KEYWORD	`nonn`
	AUTHOR	`Hugo Pfoertner (hugo(AT)pfoertner.org), May 30 2005`

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Last modified December 15 00:47 EST 2009. Contains 170825 sequences.

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