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A049098 Primes p such that p+1 is divisible by a square. 7
3, 7, 11, 17, 19, 23, 31, 43, 47, 53, 59, 67, 71, 79, 83, 89, 97, 103, 107, 127, 131, 139, 149, 151, 163, 167, 179, 191, 197, 199, 211, 223, 227, 233, 239, 241, 251, 263, 269, 271, 283, 293, 307, 311, 331, 337, 347, 349, 359, 367, 379, 383, 419, 431, 439, 443 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

Numbers m such that A010051(m)*(1-A008966(m+1)) = 1. - Reinhard Zumkeller, May 21 2009

A160696(a(n)) > 1. - Reinhard Zumkeller, May 24 2009

LINKS

T. D. Noe, Table of n, a(n) for n = 1..1000

EXAMPLE

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

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

MAPLE

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

MATHEMATICA

Select[Prime[Range[200]], !SquareFreeQ[#+1]&]   (* Harvey P. Dale, Mar 27 2011 *)

Select[Prime[Range[200]], MoebiusMu[# + 1] == 0 &] (* Alonso del Arte, Oct 18 2011 *)

PROG

(Haskell)

a049098 n = a049098_list !! (n-1)

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

-- Reinhard Zumkeller, Oct 18 2011

(PARI) forprime(p=2, 1e4, if(!issquarefree(p+1), print1(p", "))) \\ Charles R Greathouse IV, Oct 18 2011

CROSSREFS

Sequence in context: A136059 A156284 A045419 * A119992 A023249 A249682

Adjacent sequences:  A049095 A049096 A049097 * A049099 A049100 A049101

KEYWORD

nonn,easy,nice

AUTHOR

Labos Elemer

STATUS

approved

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Last modified October 22 10:24 EDT 2019. Contains 328317 sequences. (Running on oeis4.)