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A230667 Smallest starting number for n consecutive odd numbers that are primes or pseudoprime (base 2). 2

%I

%S 3,3,3,641,280743771536011781

%N Smallest starting number for n consecutive odd numbers that are primes or pseudoprime (base 2).

%C It is conjectured that the sequence is full, that is, a(6) does not exist.

%e First and smallest occurrence of n, n >= 1, consecutive odd numbers that are primes or pseudoprimes (base 2):

%e a(1) = 3: (3) ;

%e a(2) = 3: (3, 5) ;

%e a(3) = 3: (3, 5, 7);

%e a(4) = 641: (641, 643, 645, 647); (645 is pseudoprime base 2 and others are prime);

%e a(5) = 280743771536011781: (280743771536011781, 280743771536011783, 280743771536011785, 280743771536011787, 280743771536011789); (280743771536011785 is pseudoprime base 2 and others are prime).

%Y Cf. A001567, A228455.

%K nonn,hard

%O 1,1

%A _Shyam Sunder Gupta_, Oct 27 2013

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Last modified May 25 12:34 EDT 2022. Contains 354071 sequences. (Running on oeis4.)