A288639 Products of two distinct numbers that are the average of a pair of twin primes.
24, 48, 72, 108, 120, 168, 180, 216, 240, 252, 288, 360, 408, 432, 504, 540, 552, 600, 612, 648, 720, 756, 768, 792, 828, 864, 900, 912, 960, 1080, 1128, 1152, 1188, 1224, 1248, 1260, 1296, 1368, 1392, 1440, 1620, 1656, 1680, 1692, 1728, 1800, 1836, 1848
Offset: 1
Keywords
Examples
4 and 12 are two distinct numbers that are averages of twin prime pairs (i.e., 4 = (3+5)/2 and 12 = (11+13)/2), and 4*12 = 48, which is in the sequence.
Programs
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Mathematica
m = 1 + Select[Range@1000, PrimeQ[#] && PrimeQ[# + 2] &]; Select[v Union@ Flatten@ Table[m[[i]] m[[j]], {i, Length[m]}, {j, i - 1}], # <= 4000 &] (* Giovanni Resta, Jun 13 2017 *)
Extensions
More terms from Giovanni Resta, Jun 13 2017