A365448 Array read by antidiagonals: row 1 is the semiprimes A001358; for m > 1, row m is the semiprimes that are the sum of two successive terms of row m-1.
4, 6, 10, 9, 15, 25, 10, 51, 146, 422, 14, 69, 201, 551, 973, 15, 77, 221, 667, 1858, 2831, 21, 85, 249, 1191, 89855, 312493, 127418369, 22, 95, 302, 1343, 110099, 2676567, 154171217
Offset: 1
Examples
The first 7 rows are 4, 6, 9, 10, 14, 15, 21, 22, 25, 26, ... 10, 15, 51, 69, 77, 85, 95, 106, 115, 134, ... 25, 146, 201, 221, 249, 302, 365, 529, 662, 681, ... 422, 551, 667, 1191, 1343, 2661, 6621, 11207, 13637, 14183, ... 973, 1858, 89855, 110099, 202394, 332377, 352147, 383507, 469231, 528923, ... 2831, 312493, 2676567, 3754285, 4027807, 9438362, 10568289, 20372991, 20590454, 21591014, ... 127418369, 154171217, 213938227, 242408953, 296917233, 325907227, 345235903, 367725381, ... T(4,3) = 667 is a term because 667 = 23 * 29 is a semiprime and 667 = 392 + 365 where 302 = T(3,6) and 365 = T(3,7).
Programs
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Maple
R[1]:= select(t -> numtheory:-bigomega(t) = 2, [$1..5*10^6]): M[1]:= nops(R[1]): for i from 2 do R[i]:= select(t -> numtheory:-bigomega(t) = 2, R[i-1][1..M[i-1]-1] + R[i-1][2..M[i-1]]); M[i]:= nops(R[i]); if M[i] = 0 then break fi od: L:= NULL: for k from 2 to 8 do L:= L, seq(R[i][k-i],i=1..k-1) od: L;