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 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) 419-2 = 417 (3*139) 421+2 = 423 (3*3*47) 419-4 = 415 (5*83) 421+4 = 425 (5*5*17) 419-6 = 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[n-j]||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 * A350781 A097233 A233551 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

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Last modified July 12 12:19 EDT 2024. Contains 374247 sequences. (Running on oeis4.)