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Search: id:A100714
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| A100714 |
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Number of runs in binary expansion of A000040(n) (the n-th prime number) for n>0. |
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+0
7
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| 2, 1, 3, 1, 3, 3, 3, 3, 3, 3, 1, 5, 5, 5, 3, 5, 3, 3, 3, 3, 5, 3, 5, 5, 3, 5, 3, 5, 5, 3, 1, 3, 5, 5, 7, 5, 5, 5, 5, 7, 5, 7, 3, 3, 5, 3, 5, 3, 3, 5, 5, 3, 3, 3, 3, 3, 5, 3, 7, 5, 5, 7, 5, 5, 5, 5, 7, 7, 7, 7, 5, 5, 5, 7, 5, 3, 5, 5, 5, 5, 5, 7, 5, 5, 5, 5, 3, 5, 5, 3, 5, 3, 3, 5, 3, 3, 3, 5, 5, 5, 5, 7, 5, 5, 5
(list; graph; listen)
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OFFSET
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1,1
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COMMENT
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a(n)=A005811(A000040(n))
Record values of a(n)=2, 3, 5, 7, 9, 11, 13, 15, 17, 19, 21, 23, ... are set at the indices n=1, 3, 12, 35, 121, 355, 1317, 4551, 15897, 56475, 197249, 737926, ... - R. J. Mathar (mathar(AT)strw.leidenuniv.nl), Mar 02 2007
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LINKS
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Eric Weisstein's World of Mathematics, "Run-Length Encoding."
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EXAMPLE
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a(5)=3 because A000040(5)=11_10=1011_2, which splits into three runs ({1}, {0}, {1,1})
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MATHEMATICA
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Table[Length[Split[IntegerDigits[Prime[n], 2]]], {n, 1, 128}]
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CROSSREFS
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Cf. A005811, A000040.
Sequence in context: A048864 A003139 A111248 this_sequence A050123 A081386 A135591
Adjacent sequences: A100711 A100712 A100713 this_sequence A100715 A100716 A100717
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KEYWORD
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base,easy,nonn
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AUTHOR
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Joseph Biberstine (jrbibers(AT)indiana.edu), Dec 11 2004
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