

A138062


Prime number n, lesser of twin primes, both isolated from neighboring primes by more than + 6.


1



419, 521, 809, 1049, 1151, 1721, 1931, 1949, 2027, 2111, 2309, 2591, 2729, 2999, 3119, 3359, 3371, 3389, 3557, 3581, 3821, 4229, 4241, 4271, 4337, 4421, 4481, 4547, 5021, 5879, 6089, 6131, 6299, 6449, 6689, 6761, 6779, 6791, 6947, 7307, 7331, 7349, 7559
(list;
graph;
refs;
listen;
history;
text;
internal format)



OFFSET

1,1


LINKS

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


EXAMPLE

419,421 = twin primes  isolation + 6 (or more)
4192 = 417 (3*139) 421+2 = 423 (3*3*47)
4194 = 415 (5*83) 421+4 = 425 (5*5*17)
4196 = 413 (7*59) 421+6 = 427 (7*61)


MATHEMATICA

q=6; s=""; For[i=1, i<10^2*5, n=Prime[i]; m=n+2; If[PrimeQ[m], a=0; For[j=2, j<=q, If[PrimeQ[nj]PrimeQ[m+j], a=1; Break[]]; j=j+2]; If[a==0, s=s<>ToString[n]<>", "]]; i++ ]; Print[s]
tp6Q[b_]:=Module[{d=Differences[b]}, d[[2]]==2&&d[[1]]>6&&d[[3]]>6]; Transpose[ Select[Partition[Prime[Range[1000]], 4, 1], tp6Q]][[2]] (* Harvey P. Dale, Jan 10 2015 *)


CROSSREFS

Sequence in context: A224557 A292422 A328497 * A097233 A233551 A142281
Adjacent sequences: A138059 A138060 A138061 * A138063 A138064 A138065


KEYWORD

nonn


AUTHOR

Vladimir Joseph Stephan Orlovsky, May 02 2008


EXTENSIONS

Definition corrected by and more terms from Harvey P. Dale, Jan 10 2015


STATUS

approved



