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 A154725 Triangle read by rows in which row n lists 2n-1 terms: The pairs of prime numbers that are equidistant to n, with 0's inserted, as shown below in the example. 12
 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 3, 0, 5, 0, 0, 0, 0, 3, 0, 0, 0, 7, 0, 0, 0, 0, 0, 0, 5, 0, 7, 0, 0, 0, 0, 0, 0, 3, 0, 0, 0, 0, 0, 0, 0, 11, 0, 0, 0, 0, 3, 0, 5, 0, 0, 0, 0, 0, 11, 0, 13, 0, 0, 0, 0, 0, 0, 5, 0, 7, 0, 0, 0, 11, 0, 13, 0, 0, 0, 0 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,12 COMMENTS Each entry of the n-th row is either 0 or a prime p from the 2n-th row of A002260 such that 2n-p is also prime. - Jason Kimberley, Jul 08 2012 LINKS Nathaniel Johnston, Table of n, a(n) for n = 1..10000 EXAMPLE Triangle begins:                              0                           0, 0, 0                        0, 0, 0, 0, 0                     0, 0, 3, 0, 5, 0, 0                  0, 0, 3, 0, 0, 0, 7, 0, 0               0, 0, 0, 0, 5, 0, 7, 0, 0, 0, 0            0, 0, 3, 0, 0, 0, 0, 0, 0, 0,11, 0, 0         0, 0, 3, 0, 5, 0, 0, 0, 0, 0,11, 0,13, 0, 0      0, 0, 0, 0, 5, 0, 7, 0, 0, 0,11, 0,13, 0, 0, 0, 0   0, 0, 3, 0, 0, 0, 7, 0, 0, 0, 0, 0,13, 0, 0, 0,17, 0, 0 From Jason Kimberley, Jul 08 2012: (Start) Square array begins:    3,    3,    3,    0,    3,    3,    0,    3,    3, ...       0,    0,    0,    0,    0,    0,    0,    0, ...    5,    5,    5,    0,    5,    5,    0,    5, ...       0,    0,    0,    0,    0,    0,    0, ...    7,    7,    7,    0,    7,    7,    0, ...       0,    0,    0,    0,    0,    0, ...    0,    0,    0,    0,    0,    0, ...       0,    0,    0,    0,    0, ...   11,   11,   11,    0,   11, ...       0,    0,    0,    0, ...   13,   13,   13,    0, ...       0,    0,    0, ...    0,    0,    0, ...       0,    0, ...   17,   17, ...       0, ...   19, ... MAPLE for n from 1 to 10 do for k from 1 to 2*n-1 do if(not k=n and (isprime(k) and isprime(2*n-k)))then print(k):else print(0):fi:od:od: # Nathaniel Johnston, Apr 18 2011 CROSSREFS Cf. A000040, A154720, A154721, A154722, A154723, A154724, A154726, A154727. Sequence in context: A261239 A261214 A143073 * A010816 A133089 A198954 Adjacent sequences:  A154722 A154723 A154724 * A154726 A154727 A154728 KEYWORD easy,nonn,tabf AUTHOR Omar E. Pol, Jan 14 2009 STATUS approved

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Last modified July 28 12:14 EDT 2021. Contains 346328 sequences. (Running on oeis4.)