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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

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

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: A217671 A118539 A015665 * 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 October 19 21:28 EDT 2019. Contains 328244 sequences. (Running on oeis4.)