

A228455


Pseudoprimes n to base 2 such that n2, n+2, n4 and n+4 are primes.


2




OFFSET

1,1


COMMENTS

All numbers in this sequence end in 5 because n4 , n2 is a twin prime pair and so also is n+2 and n+4.
For all n, a(n)  4 is in A230668(n). Somewhat surprisingly, all terms of A230668 known so far are of that form.  M. F. Hasler, Dec 08 2016


LINKS

Table of n, a(n) for n=1..5.


EXAMPLE

280743771536011785 is a pseudoprime (base 2) and 280743771536011781, 280743771536011783, 280743771536011787 and 280743771536011789 are primes.


CROSSREFS

Cf. A001567, A057942, A230488, A230489.
Sequence in context: A337364 A058292 A230668 * A183062 A239923 A104838
Adjacent sequences: A228452 A228453 A228454 * A228456 A228457 A228458


KEYWORD

nonn,more,hard


AUTHOR

Shyam Sunder Gupta, Oct 27 2013


STATUS

approved



