A174957 Lesser of twin primes p1 such that p1*p2-4 and p1*p2-6 are twin prime numbers.

5, 11, 1031, 2711, 3851, 4421, 5867, 8837, 10067, 12041, 12251, 12611, 17957, 21491, 21521, 22037, 22481, 23537, 32141, 32411, 42641, 48311, 48731, 49367, 50261, 53231, 60167, 72167, 77417, 80147, 80447, 81047, 87641, 88337, 90527, 95231

Offset

1,1

Comments

5*7=35; 35-4=31; 35-6=29; 29,31 twin primes

Links

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

Mathematica

lst={}; Do[p1=Prime[n]; p2=p1+2; If[PrimeQ[p2]&&PrimeQ[p1*p2-4]&&PrimeQ[p1*p2-6], (*Print[p1]; *)AppendTo[lst, p1]], {n, 8!}]; lst
ltp[{a_, b_}]:=b-a==2&&AllTrue[a*b-{4, 6}, PrimeQ]; Select[Partition[Prime[ Range[ 10000]], 2, 1], ltp][[All, 1]] (* The program uses the AllTrue function from Mathematica version 10 *) (* Harvey P. Dale, Dec 07 2017 *)

Crossrefs

Cf. A001359, A174913, A174915, A174916, A174917, A174920, A174922, A174955.

Sequence in context: A056253 A101832 A046957 * A174955 A224095 A370664

Adjacent sequences: A174954 A174955 A174956 * A174958 A174959 A174960

Keyword

nonn

Author

Vladimir Joseph Stephan Orlovsky, Apr 02 2010

Status

approved