[seqfan] Chaines of semiprimes

[Zak Seidov]

sp = Semiprimes: 
4,6,9,10,14,15,21,22,25,26,... A1358

sp1 = Semiprimes that are the sum of two successive semiprimes sp:
10, 15, 51, 69, 77, 85,...A92192

sp2 = Semiprimes that are the sum of two successive semiprimes sp1: 
25,146,201,221,249,302,365,529,662,681,...

sp3 = Semiprimes that are the sum of two successive semiprimes sp2: 
422,551,667,1191,1343,2661,6621,11207,13637,...

sp4 = Semiprimes that are the sum of two successive semiprimes sp3: 
973,1858,89855,110099,202394,332377,352147,383507,469231,...

sp5 = Semiprimes that are the sum of two successive semiprimes sp4: 
2831, 312493, 2676567, 3754285, 4027807, 9438362, 10568289, 
20372991, 20590454, 21591014, 22465543, 23411767, 24693461, 
24780829, 27475705, 30645179, 31200037, 35686571, 49588817, 
49689245, 50097503, 51069094, 51280871, 52819807,...

sp6=Semiprimes that are the sum of two successive semiprimes sp5:

No sp6? 
-- 
Zak  Seidov