A228455 Pseudoprimes n to base 2 such that n-2, n+2, n-4 and n+4 are primes.

280743771536011785, 666787209284980785, 1386744766793550165, 6558237049521329745, 11646802313400102465

Offset: 1

Author

Shyam Sunder Gupta, Oct 27 2013

Keywords

• nonn
• more
• hard

Comments

All numbers in this sequence end in 5 because n-4 , n-2 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

Examples

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

Crossrefs

Cf. A001567, A057942, A230488, A230489.