A075430 - OEIS

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A075430

Primes with a squarefree neighbor.

2, 3, 5, 7, 11, 13, 23, 29, 31, 37, 41, 43, 47, 59, 61, 67, 71, 73, 79, 83, 101, 103, 107, 109, 113, 131, 137, 139, 157, 167, 173, 179, 181, 191, 193, 211, 223, 227, 229, 239, 257, 263, 277, 281, 283, 311, 313, 317, 331, 347, 353, 359, 367, 373, 383, 389, 397 (list; graph; refs; listen; history; internal format)

	OFFSET	`1,1`
	COMMENTS	`Union of A039787 and A049097; complement of A075432 in A000040.`
	LINKS	`Enrique Pérez Herrero, Table of n, a(n) for n = 1..1000`
	EXAMPLE	`a(3) = 5 because 6 (the number above) is squarefree.` `a(13) = 47 because 46 (the number below) is squarefree.` `53 is not in the sequence because both 52 and 54 have squares among their divisors.`
	PROG	`(Sage) def is_A075430(n): return is_prime(n) and (is_squarefree(n-1) or is_squarefree(n+1))` `# [D. S. McNeil, Jan 16 2011]`
	CROSSREFS	`Cf. A005117, A000040.` `Sequence in context: A067910 A171574 A181172 * A095080 A087634 A178576` `Adjacent sequences: A075427 A075428 A075429 * A075431 A075432 A075433`
	KEYWORD	`nonn`
	AUTHOR	`Reinhard Zumkeller (reinhard.zumkeller(AT)gmail.com), Sep 15 2002`

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Last modified February 15 21:56 EST 2012. Contains 205860 sequences.