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A154721
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Triangle read by rows in which row n lists 2n-1 terms: The pairs of non-composite numbers equidistant to n, with 0's inserted, as shown below in the example.
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17
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0, 1, 0, 3, 1, 0, 0, 0, 5, 1, 0, 3, 0, 5, 0, 7, 0, 0, 3, 0, 0, 0, 7, 0, 0, 1, 0, 0, 0, 5, 0, 7, 0, 0, 0, 11, 1, 0, 3, 0, 0, 0, 0, 0, 0, 0, 11, 0, 13, 0, 0, 3, 0, 5, 0, 0, 0, 0, 0, 11, 0, 13, 0, 0, 1, 0, 0, 0, 5, 0, 7, 0, 0, 0, 11, 0, 13, 0, 0, 0, 17
(list; graph; refs; listen; history; internal format)
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OFFSET
| 1,4
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LINKS
| Nathaniel Johnston, Table of n, a(n) for n = 1..10000
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EXAMPLE
| Triangle begins:
. . . . . . . . . . . . . . .0
. . . . . . . . . . . . . 1, 0, 3
. . . . . . . . . . . .1, 0, 0, 0, 5
. . . . . . . . . . 1, 0, 3, 0, 5, 0, 7
. . . . . . . . .0, 0, 3, 0, 0, 0, 7, 0, 0
. . . . . . . 1, 0, 0, 0, 5, 0, 7, 0, 0, 0,11
. . . . . .1, 0, 3, 0, 0, 0, 0, 0, 0, 0,11, 0,13
. . . . 0, 0, 3, 0, 5, 0, 0, 0, 0, 0,11, 0,13, 0, 0
. . .1, 0, 0, 0, 5, 0, 7, 0, 0, 0,11, 0,13, 0, 0, 0,17
. 1, 0, 3, 0, 0, 0, 7, 0, 0, 0, 0, 0,13, 0, 0, 0,17, 0,19
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MAPLE
| isnotcomp:=proc(n)return (n=1 or isprime(n)) end:
for n from 1 to 10 do for k from 1 to 2*n-1 do if(not k=n and (isnotcomp(k) and isnotcomp(2*n-k)))then print(k):else print(0):fi:od:od: # Nathaniel Johnston, Apr 18 2011
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CROSSREFS
| Cf. A000040, A008578, A154720, A154722, A154723, A154724, A154725, A154726, A154727.
Sequence in context: A058612 A099725 A128208 * A185664 A144209 A094544
Adjacent sequences: A154718 A154719 A154720 * A154722 A154723 A154724
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KEYWORD
| easy,nonn,tabf
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AUTHOR
| Omar E. Pol (info(AT)polprimos.com), Jan 14 2009
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