A138063 Lesser of twin primes isolated from neighboring primes by +- 10 (or more).

521, 1931, 1949, 2111, 2309, 2591, 3389, 4421, 4547, 6449, 6761, 7349, 7949, 9239, 9719, 9767, 10007, 10037, 10499, 10529, 10709, 11351, 11549, 11717, 12071, 13397, 14387, 14591, 15581, 15971, 16139, 16631, 16901, 17417, 17681, 17957, 18287, 18539, 19139, 19181

Offset

1,1

Links

Amiram Eldar, Table of n, a(n) for n = 1..10000

Example

521 is a term since (521, 523) are twin primes and
521 - 2 = 519 (3*173), 523+ 2 = 525 (3*5*7),
521 - 4 = 517 (11*43), 523+ 4 = 527 (17*31),
521 - 6 = 515 (5*103), 523+ 6 = 529 (23*23),
521 - 8 = 513 (3*3*3*19), 523+ 8 = 531 (3*3*59),
521 -10 = 511 (7*73), 523+10 = 533 (13*41).

Mathematica

q=10; 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]

Prog

(Magma) [p:p in PrimesInInterval(3, 20000)|IsPrime(p+2) and p-PreviousPrime(p) gt 10 and NextPrime(p+2)-p-2 gt 10]; // Marius A. Burtea, Dec 22 2019

Crossrefs

Cf. A001097, A001359, A006512.

Sequence in context: A113158 A004928 A004948 * A324630 A167734 A122715

Adjacent sequences: A138060 A138061 A138062 * A138064 A138065 A138066

Keyword

nonn

Author

Vladimir Joseph Stephan Orlovsky, May 02 2008

Extensions

More terms from Amiram Eldar, Dec 22 2019

Status

approved