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A083140
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Sieve of Eratosthenes arranged as an array and read by antidiagonals in the up direction; n-th row has property that smallest prime factor is prime(n).
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40
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2, 3, 4, 5, 9, 6, 7, 25, 15, 8, 11, 49, 35, 21, 10, 13, 121, 77, 55, 27, 12, 17, 169, 143, 91, 65, 33, 14, 19, 289, 221, 187, 119, 85, 39, 16, 23, 361, 323, 247, 209, 133, 95, 45, 18, 29, 529, 437, 391, 299, 253, 161, 115, 51, 20, 31, 841, 667, 551, 493, 377, 319, 203
(list;
table;
graph;
refs;
listen;
history;
text;
internal format)
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OFFSET
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2,1
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COMMENTS
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A permutation of natural numbers >= 2.
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LINKS
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Table of n, a(n) for n=2..64.
Index entries for sequences that are permutations of the natural numbers
Index entries for sequences generated by sieves
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EXAMPLE
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Array begins:
2 4 6 8 10 12 14 16 18 20 22 24 .... (A005843)
3 9 15 21 27 33 39 45 51 57 63 69 .... (A016945)
5 25 35 55 65 85 95 115 125 145 155 175 .... (A084967)
7 49 77 91 119 133 161 203 217 259 287 301 .... (A084968)
11 121 143 187 209 253 319 341 407 451 473 517 .... (A084969)
13 169 221 247 299 377 403 481 533 559 611 689 .... (A084970)
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MATHEMATICA
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a = Join[ {Table[2n, {n, 1, 12}]}, Table[ Take[ Prime[n]*Select[ Range[100], GCD[ Prime[n] #, Product[ Prime[i], {i, 1, n - 1}]] == 1 &], 12], {n, 2, 12}]]; Flatten[ Table[ a[[i, n - i]], {n, 2, 12}, {i, n - 1, 1, -1}]]
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CROSSREFS
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Cf. A083141 (main diagonal), A083221 (transpose), A004280, A038179, A084967, A084968, A084969, A084970, A084971.
Sequence in context: A119586 A095904 A096153 * A246279 A253565 A124652
Adjacent sequences: A083137 A083138 A083139 * A083141 A083142 A083143
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KEYWORD
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nonn,tabl,nice,changed
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AUTHOR
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Yasutoshi Kohmoto (zbi74583(AT)boat.zero.ad.jp), Jun 05 2003
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EXTENSIONS
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More terms from Hugo Pfoertner and Robert G. Wilson v, Jun 13 2003
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STATUS
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approved
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