A194427 Indices k of twin prime averages A014574 which are two thirds of another twin prime average.

1, 3, 8, 13, 21, 47, 65, 99, 143, 209, 214, 227, 233, 234, 244, 260, 277, 283, 297, 328, 353, 399, 409, 431, 451, 509, 516, 533, 543, 671, 675, 677, 701, 737, 741, 748, 767, 786, 795, 804, 854, 856, 890, 937, 981, 986, 992, 994, 1014, 1080, 1098, 1129, 1130, 1160, 1200, 1213, 1222, 1227, 1258

Offset

1,2

Links

Robert Israel, Table of n, a(n) for n = 1..2500

Example

3 is in the sequence because A014574(3)=12 is two thirds of 18 and 18 is also a twin prime average.

Maple

TPA:= 4: count:= 1:
for p from 5 by 6 while count < 2000 do
  if isprime(p) and isprime(p+2) then count:= count+1; TPA:= TPA, p+1;  fi
od:
TPA:= [TPA]:
TPAS:= convert(TPA, set):
T3:= map(`*`, TPAS, 2/3) intersect TPAS:
V:= Vector(nops(T3), proc(i) local k; member(T3[i], TPA, 'k'); k end proc):
convert(V, list); # Robert Israel, Aug 26 2025

Crossrefs

Cf. A014574.

Sequence in context: A212649 A084535 A351355 * A335048 A185954 A051838

Adjacent sequences: A194424 A194425 A194426 * A194428 A194429 A194430

Keyword

nonn

Author

Juri-Stepan Gerasimov, Dec 02 2011

Status

approved