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A154726 Triangle read by rows in which row n lists: n, in the center of the row and the pairs of prime numbers that are equidistant to n, as shown below in the example.

%I A154726 #14 Apr 26 2025 15:26:19
%S A154726 1,2,3,3,4,5,3,5,7,5,6,7,3,7,11,3,5,8,11,13,5,7,9,11,13,3,7,10,13,17,
%T A154726 3,5,11,17,19,5,7,11,12,13,17,19,3,7,13,19,23,5,11,14,17,23,7,11,13,
%U A154726 15,17,19,23,3,13,16,19,29,3,5,11,17,23,29
%N A154726 Triangle read by rows in which row n lists: n, in the center of the row and the pairs of prime numbers that are equidistant to n, as shown below in the example.
%H A154726 Nathaniel Johnston, <a href="/A154726/b154726.txt">Table of n, a(n) for n = 1..10000</a>
%e A154726 Triangle begins:
%e A154726                        1
%e A154726                        2
%e A154726                        3
%e A154726                     3  4  5
%e A154726                  3  .  5  .  7
%e A154726               .  .  5  6  7  .  .
%e A154726            3  .  .  .  7  .  .  . 11
%e A154726         3  .  5  .  .  8  .  . 11  . 13
%e A154726      .  .  5  .  7  .  9  . 11  . 13  .  .
%e A154726   3  .  .  .  7  .  . 10  .  . 13  .  .  . 17
%p A154726 for n from 1 to 10 do for k from 1 to 2*n-1 do if(k=n or (isprime(k) and isprime(2*n-k)))then print(k):fi:od:od: # _Nathaniel Johnston_, Apr 18 2011
%t A154726 Select[Flatten@Table[If[k == n  || ( PrimeQ[k] && PrimeQ[2 n - k]), k, 0], {n, 10}, {k, 2 n - 1}] , # > 0 &] (* _Robert Price_, Apr 26 2025 *)
%Y A154726 Cf. A000040, A154720, A154721, A154722, A154723, A154724, A154725, A154727.
%K A154726 easy,nonn,tabf
%O A154726 1,2
%A A154726 _Omar E. Pol_, Jan 14 2009
%E A154726 a(31)-a(70) from _Nathaniel Johnston_, Apr 18 2011