%I A154723
%S A154723 1,1,3,1,5,1,3,5,7,3,7,1,5,7,11,1,3,11,13,3,5,11,13,1,5,7,11,13,17,1,3,
               7,
%T A154723 13,17,19
%N A154723 Triangle read by rows in which row n lists all the pairs of non-composite 
               numbers that are equidistant from n, or only n if there are no such 
               pairs, as shown below in the example.
%e A154723 Triangle begins:
%e A154723 . . . . . . . . . . . . . . .1
%e A154723 . . . . . . . . . . . . . 1, .. 3
%e A154723 . . . . . . . . . . . .1, .. .. .. 5
%e A154723 . . . . . . . . . . 1, .. 3, .. 5, .. 7
%e A154723 . . . . . . . . . . .. 3, .. .. .. 7, .. .
%e A154723 . . . . . . . 1, .. .. .. 5, .. 7, .. .. .,11
%e A154723 . . . . . .1, .. 3, .. .. .. .. .. .. ..11, ..13
%e A154723 . . . . .. .. 3, .. 5, .. .. .. .. ..11, ..13, .. .
%e A154723 . . .1, .. .. .. 5, .. 7, .. .. ..11, ..13, .. .. ..17
%e A154723 . 1, .. 3, .. .. .. 7, .. .. .. .. ..13, .. .. ..17, ..19
%Y A154723 Cf. A000040, A008578, A154720, A154721, A154722, A154724, A154725, A154726, 
               A154727.
%Y A154723 Sequence in context: A016475 A037227 A056753 this_sequence A114567 A001051 
               A046730
%Y A154723 Adjacent sequences: A154720 A154721 A154722 this_sequence A154724 A154725 
               A154726
%K A154723 easy,more,nonn,tabf
%O A154723 1,3
%A A154723 Omar E. Pol (info(AT)polprimos.com), Jan 14 2009, Jan 16 2009