A035791 Start of a string of exactly 3 consecutive (but disjoint) pairs of twin primes.

5, 179, 809, 3359, 4217, 6761, 18041, 21587, 26861, 49367, 67187, 80447, 82721, 91127, 97841, 98897, 103967, 109829, 122597, 154157, 178037, 203321, 208931, 225749, 227609, 236867, 243671, 251201, 266447, 285611, 289109, 295871, 317729

Offset

1,1

References

Posting to Number Theory List (NMBRTHRY(AT)LISTSERV.NODAK.EDU), Nov. 19 1998.

Links

Sebastian Petzelberger, Table of n, a(n) for n = 1..10000

Example

a(2)=179 because (179,181),(191,193),(197,199) is the second occurrence (after (5,7),(11,13),(17,19)) of exactly 3 pairs of twin primes.

Mathematica

Select[Prime@ Range@ 30000, And[ NextPrime[#, -1] - NextPrime[#, -2] != 2, NextPrime@ # - # == 2, NextPrime[#, 3] - NextPrime[#, 2] == 2, NextPrime[#, 5] - NextPrime[#, 4] == 2, NextPrime[#, 7] - NextPrime[#, 6] > 2] &] (* Michael De Vlieger, Apr 25 2015 *)
Select[Partition[Prime[Range[30000]], 10, 1], #[[8]]-#[[7]]==#[[6]]-#[[5]] == #[[4]] - #[[3]]==2&&#[[2]]-#[[1]]!=2&&#[[10]]-#[[9]]!=2&][[All, 3]] (* Harvey P. Dale, Mar 14 2018 *)

Crossrefs

Cf. A035789, A035790, A035792, A035793, A035794, A035795, A087641.

Sequence in context: A210931 A141981 A136143 * A324090 A250327 A366342

Adjacent sequences: A035788 A035789 A035790 * A035792 A035793 A035794

Keyword

nonn,easy

Author

Randall L Rathbun

Extensions

More terms from Hugo Pfoertner, Sep 05 2003

Offset corrected by Arkadiusz Wesolowski, May 06 2012

Status

approved