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%I #10 Dec 08 2015 08:56:30
%S 1,1,2,3,1,0,3,0,5,1,0,3,4,5,0,7,0,0,3,0,5,0,7,0,0,1,0,0,0,5,6,7,0,0,
%T 0,11,1,0,3,0,0,0,7,0,0,0,11,0,13,0,0,3,0,5,0,0,8,0,0,11,0,13,0,0,1,0,
%U 0,0,5,0,7,0,9,0,11,0,13,0,0,0,17
%N Triangle read by rows in which row n lists 2n-1 terms: n, in the center of the row and all the pairs of noncomposite numbers equidistant to n, with 0's inserted, as shown below in the example.
%H Nathaniel Johnston, <a href="/A154720/b154720.txt">Table of n, a(n) for n = 1..10000</a>
%e Triangle begins:
%e 1
%e 1 2 3
%e 1 0 3 0 5
%e 1 0 3 4 5 0 7
%e 0 0 3 0 5 0 7 0 0
%e 1 0 0 0 5 6 7 0 0 0 11
%e 1 0 3 0 0 0 7 0 0 0 11 0 13
%e 0 0 3 0 5 0 0 8 0 0 11 0 13 0 0
%e 1 0 0 0 5 0 7 0 9 0 11 0 13 0 0 0 17
%e 1 0 3 0 0 0 7 0 0 10 0 0 13 0 0 0 17 0 19
%p isnotcomp:=proc(n)return (n=1 or isprime(n)) end:
%p for n from 1 to 10 do for k from 1 to 2*n-1 do if(k=n or (isnotcomp(k) and isnotcomp(2*n-k)))then print(k):else print(0):fi:od:od: # _Nathaniel Johnston_, Apr 18 2011
%Y Cf. A000040, A008578, A154721-A154727.
%K easy,nonn,tabf
%O 1,3
%A _Omar E. Pol_, Jan 14 2009
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