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%I #21 Jun 26 2017 08:01:00
%S 1,3,2,9,6,4,17,13,7,5,40,26,19,11,8,56,48,31,23,15,10,90,75,61,39,28,
%T 18,12,114,103,79,68,44,34,20,14,164,135,122,94,81,54,37,24,16,253,
%U 199,172,152,118,101,65,49,30,21
%N Array T(i,k) read by antidiagonals: position of prime(i)*prime(k) in A001358.
%e Array begins:
%e 1 2 4 5 8 10 12 14 16 21
%e 3 6 7 11 15 18 20 24 30
%e 9 13 19 23 28 34 37 49
%e 17 26 31 39 44 54 65
%e 40 48 61 68 81 101
%e 56 75 79 94 118
%e 90 103 122 152
%e 114 135 172
%e 164 199
%e 253
%t With[{nn = 11}, Function[s, Table[Position[s, Prime[i] Prime[k]][[1, 1]], {i, nn}, {k, i, 1, -1}] // Flatten]@ Select[Range[Prime[nn]^2], PrimeOmega@ # == 2 &]] (* _Michael De Vlieger_, Jun 23 2017 *)
%Y Cf. A000040, A001358, A115392 (1st row), A128301 (1st column).
%K nonn,tabl
%O 1,2
%A _Zak Seidov_, Jun 23 2017
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