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Search: id:A140755
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| A140755 |
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A prime array is embedded in a binary quadratic equation that is a transform of x^2 -x + 41. |
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+0
3
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| 43, 47, 53, 61, 71, 83, 97, 113, 131, 151, 173, 197, 223, 251, 281, 313, 347, 383, 421, 461, 167, 172, 179
(list; graph; listen)
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OFFSET
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1,1
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FORMULA
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41b^2 + ab + a^2, a = column 1:20, b = row 1:8, factor the row number b starting at b = 2 and remove all prime factors in b (on row 2 just 2's) from all terms on the row. Repeat the process for all rows. The numbers that remain at the end of the process in the 20*8 array will all be prime
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EXAMPLE
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a = 16, b = 2, S(16,2) = 452, 452/2 = 226, 226/2 = 113 (a prime}
a = 6, b = 3, S(6,3) = 423, 423/3 = 141, 141/3 = 47 (a prime}
a = 6, b = 6, S(6,6) = 1548, 1548/2 = 774, 774/2 = 387, 387/3 = 129,
129/3 = 43 (a prime}
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CROSSREFS
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Cf. A140754.
Sequence in context: A095503 A095495 A095487 this_sequence A095479 A033230 A118485
Adjacent sequences: A140752 A140753 A140754 this_sequence A140756 A140757 A140758
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KEYWORD
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nonn,uned
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AUTHOR
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Aldrich Stevens (aldrichstevens(AT)msn.com), May 27 2008
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EXTENSIONS
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Definition is not clear to me. How is this related to the very similar sequence A140340? - njas, Jun 04 2008
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