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A230810 Smallest of 3 consecutive odd numbers that are primes or strong pseudoprime to base 2. 2
3, 3465253618399, 374166120095639, 12959269432331237, 44202753561285409, 1640293473202755797, 1640293473202755799, 10623546148468360249 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

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

LINKS

Table of n, a(n) for n=1..8.

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

EXAMPLE

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.

CROSSREFS

Cf. A001262, A001567, A230667, A230808.

Sequence in context: A260002 A058447 A275939 * A266199 A216148 A058453

Adjacent sequences:  A230807 A230808 A230809 * A230811 A230812 A230813

KEYWORD

nonn,hard,more

AUTHOR

Shyam Sunder Gupta, Oct 30 2013

EXTENSIONS

Edited by M. F. Hasler, Dec 08 2016

STATUS

approved

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Last modified September 16 12:34 EDT 2019. Contains 327098 sequences. (Running on oeis4.)