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A103513
Primes of the form primorial(P(k))/2-2^n with minimal n, n>=0, k>=2.
1
2, 13, 103, 1153, 15013, 255253, 4849843, 111546433, 3234846607, 100280245063, 3710369067401, 152125131763603, 6541380632280583, 307444891294245701, 16294579238595022363, 961380175077106319471, 58644190679703485491571
OFFSET
1,1
COMMENTS
The Mathematica Program does not produce a(2). Conjecture: sequence is defined for all k>=2.
EXAMPLE
P(2)/2=3, 3-2^0=2 is prime, so a(2)=2;
P(5)/2=1155, 1155-2^1=1153 is prime, so a(5)=1153;
MATHEMATICA
nmax = 2^8192; npd = 1; n = 2; npd = npd*Prime[n]; While[npd < nmax, tt = 2; cp = npd - tt; While[(cp > 1) && (! (PrimeQ[cp])), tt = tt*2; cp = npd - tt]; If[cp < 2, Print["*"], Print[cp]]; n = n + 1; npd = npd*Prime[n]]
KEYWORD
nonn
AUTHOR
Lei Zhou, Feb 15 2005
STATUS
approved