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A249305 Primes n such that 2^n - n^2 is not squarefree. 0
2, 89, 149, 151, 383, 409 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

Sequence is infinite, containing all primes equal to 2, 4, 89, or 115 mod 147. - Charles R Greathouse IV, Oct 28 2014

LINKS

Table of n, a(n) for n=1..6.

FORMULA

a(n) < (21 + e)n log n for any e > 0 and all large enough n. - Charles R Greathouse IV, Oct 28 2014

EXAMPLE

2 is in this sequence because 2 is prime and 2^2 - 2^2 = 0 is not squarefree.

PROG

(MAGMA) [n: n in [3..269] | IsPrime(n) and not IsSquarefree(2^n - n^2)];

(PARI) is(n)=isprime(n) && !issquarefree(2^n-n^2) \\ Charles R Greathouse IV, Oct 28 2014

CROSSREFS

Cf. A005117, A024012.

Sequence in context: A139881 A161676 A235467 * A023302 A041967 A226768

Adjacent sequences:  A249302 A249303 A249304 * A249306 A249307 A249308

KEYWORD

nonn,more

AUTHOR

Juri-Stepan Gerasimov, Oct 25 2014

EXTENSIONS

a(5)-a(6) from Charles R Greathouse IV, Oct 28 2014

STATUS

approved

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Last modified November 15 06:11 EST 2019. Contains 329144 sequences. (Running on oeis4.)