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 A230667 Smallest starting number for n consecutive odd numbers that are primes or pseudoprime (base 2). 2
 3, 3, 3, 641, 280743771536011781 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,1 COMMENTS It is conjectured that the sequence is full, that is, a(6) does not exist. LINKS EXAMPLE First and smallest occurrence of n, n >= 1, consecutive odd numbers that are primes or pseudoprimes (base 2): a(1) = 3: (3) ; a(2) = 3: (3, 5) ; a(3) = 3: (3, 5, 7); a(4) = 641: (641, 643, 645, 647); (645 is pseudoprime base 2 and others are prime); a(5) = 280743771536011781: (280743771536011781, 280743771536011783, 280743771536011785, 280743771536011787, 280743771536011789); (280743771536011785 is pseudoprime base 2 and others are prime). CROSSREFS Cf. A001567, A228455. Sequence in context: A118539 A015665 A343120 * A131462 A230811 A117032 Adjacent sequences:  A230664 A230665 A230666 * A230668 A230669 A230670 KEYWORD nonn,hard AUTHOR Shyam Sunder Gupta, Oct 27 2013 STATUS approved

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Last modified January 18 00:30 EST 2022. Contains 350410 sequences. (Running on oeis4.)