A060230 Smaller of twin primes whose middle term is a multiple of A002110(4)=210.

419, 1049, 2309, 2729, 3359, 5879, 6089, 6299, 7349, 7559, 8819, 9239, 10499, 10709, 11549, 11969, 15329, 18059, 21839, 25409, 26249, 26879, 28349, 29399, 30869, 31079, 32969, 33179, 33599, 33809, 34649, 35279, 37589, 40529, 42839

Offset: 1

Author

Labos Elemer, Mar 21 2001

Keywords

• nonn

Comments

Number of terms less than 10^k: 0, 0, 0, 1, 12, 80, 542, 3908, 29229, ... - Muniru A Asiru, Jan 29 2018

Examples

			For the pair {1049,1051} (1049+1051)/2 = 5*210.
		

Links

• Harvey P. Dale, Table of n, a(n) for n = 1..1000

Crossrefs

A001359, A002110, A060229, A060231.

Programs

GAP

P:=Filtered([1..10^7], IsPrime);;
P1:=List(Filtered(Filtered(List([1..Length(P)-1], n -> [P[n],P[n+1]]), i -> i[2]-i[1]=2), j -> (j[1]+j[2]) mod 210 = 0), k -> k[1]); # Muniru A Asiru, Jan 29 2018

Maple

select(n->isprime(n) and isprime(n+2), [seq(210*k - 1, k=1..10^3)]); # Muniru A Asiru, Jan 29 2018

Mathematica

Select[210*Range[250],And@@PrimeQ[#+{1,-1}]&]-1 (* Harvey P. Dale, Aug 25 2013 *)

PARI

is(n)=(n+1)%210==0 && isprime(n+2) && isprime(n) \\ Charles R Greathouse IV, Jan 29 2018

Extensions

Minor edits by Ray Chandler, Apr 02 2009