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A075430 Primes with a squarefree neighbor. 5
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; text; internal format)
OFFSET

1,1

COMMENTS

Union of A039787 and A049097; complement of A075432 in A000040.

LINKS

Enrique PĂ©rez 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: A296236 A334041 A181172 * A095080 A229289 A087634

Adjacent sequences:  A075427 A075428 A075429 * A075431 A075432 A075433

KEYWORD

nonn

AUTHOR

Reinhard Zumkeller, Sep 15 2002

STATUS

approved

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Last modified August 7 15:30 EDT 2020. Contains 336276 sequences. (Running on oeis4.)