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A060230 Smaller of twin primes whose middle term is a multiple of A002110(4)=210. 5
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 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

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

LINKS

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

EXAMPLE

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

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 *)

PROG

(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

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

CROSSREFS

A001359, A002110, A060229, A060231.

Sequence in context: A142281 A242281 A142733 * A255097 A130737 A242326

Adjacent sequences:  A060227 A060228 A060229 * A060231 A060232 A060233

KEYWORD

nonn

AUTHOR

Labos Elemer, Mar 21 2001

EXTENSIONS

Minor edits by Ray Chandler, Apr 02 2009

STATUS

approved

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Last modified November 26 07:25 EST 2020. Contains 338632 sequences. (Running on oeis4.)