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Search: id:A100634
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| A100634 |
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a(n) = decimal equivalent of binary number whose k-th least significant bit is 1 iff k is a prime number and k <= n. |
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+0
2
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| 0, 2, 6, 6, 22, 22, 86, 86, 86, 86, 1110, 1110, 5206, 5206, 5206, 5206, 70742, 70742, 332886, 332886, 332886, 332886, 4527190, 4527190, 4527190, 4527190, 4527190, 4527190, 272962646, 272962646, 1346704470, 1346704470, 1346704470
(list; graph; listen)
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OFFSET
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1,2
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COMMENT
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1 is not considered prime. If 1 were to be considered prime, each term would be incremented by 1.
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LINKS
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T. D. Noe, Table of n, a(n) for n=1..300
Eric Weisstein's World of Mathematics, "Least Significant Bit."
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EXAMPLE
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a(5)=22 because the k-th least significant bits 1,2,3,4,5 are prime for 2,3,5 and not prime for 1,4. So k=1->0, k=2->1, k=3->1, k=4->0 and k=5->1 gives the bit sequence 10110, which is 2+4+16=22 in its decimal expansion.
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MAPLE
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Table[FromDigits[Reverse[Table[If[PrimeQ[k] == True, 1, 0], {k, 1, N}]], 2], {N, 1, 40}]
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CROSSREFS
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Cf. A000040, A080355, A080339.
Cf. A072762
Sequence in context: A081518 A135616 A119551 this_sequence A130865 A105725 A005226
Adjacent sequences: A100631 A100632 A100633 this_sequence A100635 A100636 A100637
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KEYWORD
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nonn
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AUTHOR
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Joseph Biberstine (jrbibers(AT)indiana.edu), Dec 02 2004
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