A230810 -id:A230810 - cp's OEIS frontend

A230485 Strong pseudoprimes n to base 2 such that n-2 and n+2 are primes.

3465253618401, 44202753561285411, 1640293473202755801, 10623546148468360251

Offset: 1

Shyam Sunder Gupta, Oct 20 2013

For all n, a(n)-2 is in A230810. - M. F. Hasler, Dec 08 2016

			3465253618401 is a strong pseudoprime (base 2) and 3465253618399 and 3465253618403 are primes.

Cf. A001567, A057942, A001262, A230483, A230484.

A230811 Smallest starting number for n consecutive odd numbers that are primes or strong pseudoprime (base 2).

Original entry on oeis.org

3, 3, 3, 1640293473202755797

Offset: 1

Shyam Sunder Gupta, Oct 30 2013

It is conjectured that there can be at most one more term, a(5).

			First and smallest occurrence of n, n >= 1, consecutive odd numbers that are primes or strong pseudoprime (base 2):
a(1) = 3: (3) ;
a(2) = 3: (3, 5) ;
a(3) = 3: (3, 5, 7);
a(4) = 1640293473202755797: (1640293473202755797, 1640293473202755799, 1640293473202755801, 1640293473202755803); (1640293473202755801 is strong pseudoprime base 2 and others are prime);

Cf. A001567, A001262, A230667, A230810.

cp's OEIS Frontend

A230485 Strong pseudoprimes n to base 2 such that n-2 and n+2 are primes.

Views

Author

Keywords

Comments

Examples

Crossrefs