A365145 Lexicographically least increasing sequence of triprimes (A014612) whose first differences are triprimes.
8, 20, 28, 70, 78, 98, 110, 130, 138, 165, 195, 207, 273, 285, 363, 426, 434, 442, 470, 498, 506, 518, 530, 548, 556, 574, 582, 590, 598, 606, 618, 638, 646, 654, 682, 710, 722, 730, 742, 754, 762, 782, 790, 834, 854, 874, 892, 942, 962, 970, 978, 986, 994, 1002, 1010, 1022, 1030, 1038, 1058
Offset: 1
Keywords
Examples
a(2) = 20, a(3) = 28 = 2^2 * 7 is a triprime and 28 - 20 = 8 = 2^3 is a triprime, and this is the least number > 20 that works, so a(4) = 28.
Links
- Robert Israel, Table of n, a(n) for n = 1..10000
Programs
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Maple
R:= 8: m:= 8: count:= 1: for t from 9 while count < 100 do if numtheory:-bigomega(t) = 3 and numtheory:-bigomega(t-m) = 3 then R:= R,t; m:= t; count:= count+1 fi od: R; -
Mathematica
Do[n = m + 8; While[{3, 3} != PrimeOmega[{n, n - m}], n++]; AppendTo[s, m = n], {100}]; s
Comments