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

3, 3, 3, 641, 280743771536011781

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: A118539 A015665 A343120 * A131462 A230811 A374362

Adjacent sequences: A230664 A230665 A230666 * A230668 A230669 A230670

Keyword

nonn,hard

Author

Shyam Sunder Gupta, Oct 27 2013

Status

approved