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A087716 Base-2 pseudoprimes (see A001567) of the form j*p(i)# - p(k) or j*p(i)# + p(k), p(i) and p(k) primes with p(i) < p(k) < p(i+1)^2 and 0 < j < p(i+1). 3
341, 1387, 2047, 4681, 13747 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

Conjecture: sequence has only 5 terms. This has been checked for all i <= 150.

LINKS

Table of n, a(n) for n=1..5.

Index entries for sequences related to pseudoprimes

EXAMPLE

   2*7#  -  79 =   341,

   7*7#  -  83 =  1387,

  10*7#  -  53 =  2047,

   2*11# +  61 =  4681,

   6*11# - 113 = 13747,

  13*7#  -  29 =  2701.

PROG

(PARI) lst(lim)=my(p=2, P=1, v=List()); forprime(q=3, lim, P*=p; forprime(r=q, q^2, for(j=1, q-1, if(j*P-r>340&&psp(j*P-r), listput(v, j*P-r)); if(psp(j*P+r), listput(v, j*P+r)))); p=q); vecsort(Vec(v), , 8) \\ Charles R Greathouse IV, Apr 12 2012

CROSSREFS

Cf. A001567, A087714, A087715, A087728.

# denotes primorials; see A002110.

Sequence in context: A214305 A086837 A020230 * A084653 A143688 A086250

Adjacent sequences:  A087713 A087714 A087715 * A087717 A087718 A087719

KEYWORD

nonn,more

AUTHOR

Pierre CAMI, Sep 29 2003

EXTENSIONS

Edited by David Wasserman, Apr 13 2006

STATUS

approved

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Last modified May 18 23:58 EDT 2021. Contains 344009 sequences. (Running on oeis4.)