A069456 Non-twin primes that are at least doubly lonely.

1039, 2099, 4253, 91121, 386401, 626617, 754973, 873553, 908857, 972137, 1619353, 1749067, 1841681, 2007899, 2169007, 2241353, 2420633, 2484931, 2594971, 3075323, 3129601, 3151843, 3837451, 3843247, 3919229, 4038709, 4545683, 5502449, 5530529, 5921869

Offset

1,1

Links

Arkadiusz Wesolowski, Table of n, a(n) for n = 1..10000

Example

These are non-twin primes sandwiched between at least 2 pairs of twins on each side. The first number in the sequence is 1039 (sandwiched between 1019,1021,1031,1033 and 1049,1051,1061,1063).

Maple

Primes:= select(isprime, [seq(i, i=3..6*10^6, 2)]):
good:= select(t -> Primes[t-3]-Primes[t-4]=2 and Primes[t-1]-Primes[t-2]=2 and Primes[t+2]-Primes[t+1]=2 and Primes[t+4]-Primes[t+3]=2, [$5..nops(Primes)-4]):
Primes[good]; # Robert Israel, May 13 2016

Mathematica

dltpQ[{a_, b_, c_, d_, e_, f_, g_, h_, i_}]:=b-a==d-c==g-f==i-h==2; Transpose[ Select[ Partition[Prime[Range[410000]], 9, 1], dltpQ]][[5]] (* Harvey P. Dale, May 14 2013 *)

Crossrefs

Cf. A007510, A069453.

Sequence in context: A235156 A288413 A020395 * A210259 A233854 A168412

Adjacent sequences: A069453 A069454 A069455 * A069457 A069458 A069459

Keyword

nonn

Author

Neil Fernandez, Mar 23 2002

Extensions

More terms from Arkadiusz Wesolowski, May 08 2012

Status

approved