A230810 Smallest of 3 consecutive odd numbers that are primes or strong pseudoprime to base 2.

3, 3465253618399, 374166120095639, 12959269432331237, 44202753561285409, 1640293473202755797, 1640293473202755799, 10623546148468360249

Offset: 1

Author

Shyam Sunder Gupta, Oct 30 2013

Keywords

• nonn
• hard
• more

Comments

Since a(7) = a(6) + 2, the number a(6) = 1640293473202755797 actually starts a sequence of four consecutive odd numbers which are prime or strong pseudoprimes to base 2. - M. F. Hasler, Dec 08 2016

Examples

			3465253618399 is in sequence because 3465253618399, 3465253618401, 3465253618403 is a set of 3 consecutive odd number where 3465253618401 is strong pseudoprime base 2 and others are prime.
		

Links

• S. S. Gupta, Can You Find no. 48, Oct. 2016.

Crossrefs

Cf. A001262, A001567, A230667, A230808.

Extensions

Edited by M. F. Hasler, Dec 08 2016