A230667 -id:A230667 - cp's OEIS frontend

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

Shyam Sunder Gupta, Oct 30 2013

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

			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.

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

Cf. A001262, A001567, A230667, A230808.

Edited by M. F. Hasler, Dec 08 2016

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

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

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