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 A049098 Primes p such that p+1 is divisible by a square. 7

%I

%S 3,7,11,17,19,23,31,43,47,53,59,67,71,79,83,89,97,103,107,127,131,139,

%T 149,151,163,167,179,191,197,199,211,223,227,233,239,241,251,263,269,

%U 271,283,293,307,311,331,337,347,349,359,367,379,383,419,431,439,443

%N Primes p such that p+1 is divisible by a square.

%C Numbers m such that A010051(m)*(1-A008966(m+1)) = 1. - _Reinhard Zumkeller_, May 21 2009

%C A160696(a(n)) > 1. - _Reinhard Zumkeller_, May 24 2009

%H T. D. Noe, <a href="/A049098/b049098.txt">Table of n, a(n) for n = 1..1000</a>

%e 31 is here because 32 is divisible by a square, 16.

%e 101 is not here because 102=2*3*17 is squarefree.

%p with(numtheory): a := proc (n) if isprime(n) = true and issqrfree(n+1) = false then n else end if end proc: seq(a(n), n = 1 .. 500); # _Emeric Deutsch_, Jun 21 2009

%t Select[Prime[Range],!SquareFreeQ[#+1]&] (* _Harvey P. Dale_, Mar 27 2011 *)

%t Select[Prime[Range], MoebiusMu[# + 1] == 0 &] (* _Alonso del Arte_, Oct 18 2011 *)

%o a049098 n = a049098_list !! (n-1)

%o a049098_list = filter ((== 0) . a008966 . (+ 1)) a000040_list

%o -- _Reinhard Zumkeller_, Oct 18 2011

%o (PARI) forprime(p=2,1e4,if(!issquarefree(p+1),print1(p", "))) \\ _Charles R Greathouse IV_, Oct 18 2011

%K nonn,easy,nice

%O 1,1

%A _Labos Elemer_

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Last modified November 13 02:59 EST 2019. Contains 329085 sequences. (Running on oeis4.)