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A085988 Triangle of least prime signatures such that T(1,1)= 1; T(r,j) = 2*T(r,j-1) for j>1 and T(r+1,1) is the smallest value in A025487 not appearing on an earlier row.

%I A085988 #7 Feb 20 2019 17:10:24
%S A085988 1,2,4,6,12,24,8,16,32,64,30,60,120,240,480,36,72,144,288,576,1152,48,
%T A085988 96,192,384,768,1536,3072,128,256,512,1024,2048,4096,8192,16384,180,
%U A085988 360,720,1440,2880,5760,11520,23040,46080,210,420,840,1680,3360,6720,13440,26880,53760,107520
%N A085988 Triangle of least prime signatures such that T(1,1)= 1; T(r,j) = 2*T(r,j-1) for j>1 and T(r+1,1) is the smallest value in A025487 not appearing on an earlier row.
%e A085988 The table begins:
%e A085988    1
%e A085988    2  4
%e A085988    6 12  24
%e A085988    8 16  32  64
%e A085988   30 60 120 240 480
%e A085988   36 72 144 288 576 1152
%e A085988   ...
%o A085988 (PARI) isli(n) = if(n==1, return(1)); my(f = factor(n)); f[#f~, 1] == prime(#f~) && vecsort(f[, 2], , 4) == f[, 2]; \\ A025487
%o A085988 findfirst(all, used) = {for (k=1, #all, if (!vecsearch(used, all[k]), return (all[k])););}
%o A085988 tabl(nn) = {all = select(x->isli(x), vector(nn, k, k)); used = []; for (n=1, oo, if (n==1, row = [1], first = findfirst(all, used); if (!first, return); row = vector(n, k, first*2^(k-1))); print(row); used = vecsort(concat(used, row)););} \\ _Michel Marcus_, Feb 20 2019
%Y A085988 Cf. A025487, A056153, A062515.
%K A085988 easy,nonn,tabl
%O A085988 1,2
%A A085988 _Alford Arnold_, Jul 12 2003
%E A085988 More terms from _Michel Marcus_, Feb 20 2019