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Search: id:A110095
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| A110095 |
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Least increasing sequence of nonprimes whose first differences are also nonprime. |
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+0
2
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| 0, 1, 9, 10, 14, 15, 16, 20, 21, 22, 26, 27, 28, 32, 33, 34, 35, 36, 40, 44, 45, 46, 50, 51, 52, 56, 57, 58, 62, 63, 64, 65, 66, 70, 74, 75, 76, 77, 78, 82, 86, 87, 88, 92, 93, 94, 95, 96, 100, 104, 105, 106, 110, 111, 112, 116, 117, 118, 119, 120, 121, 122, 123, 124, 125
(list; graph; listen)
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OFFSET
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1,3
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COMMENT
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The sequence of first differences contains only 1's and 4's (with an 8 at the beginning): 1 8 1 4 1 1 4 1 1 4 1 1 4 1 1 1 1 4 4 1 1 4 1 1 4 1 1 4 1 1 1 1 4 4 1 1 1 1 4 4 1 1 4 1 1 1 1 4 4
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EXAMPLE
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Begin with a(1)=0. Add to a(1) the least non prime giving a non prime number: + 1 = 1 for a(2). Now add to a(2) the least non prime giving a composite: + 8 = 9 for a(3). Same rule: + 1 = 10 for a(4). Same rule: + 4 = 14 etc...
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MATHEMATICA
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f[s_List] := Block[{j = s[[ -1]]}, k = j + 1; While[PrimeQ[k] || PrimeQ[k - j], k++ ]; Append[s, k]]; Nest[f, {0}, 64] (* Robert G. Wilson v Sep 23 2006 *)
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CROSSREFS
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Cf. A109888.
Sequence in context: A154766 A116594 A050593 this_sequence A061445 A088710 A020199
Adjacent sequences: A110092 A110093 A110094 this_sequence A110096 A110097 A110098
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KEYWORD
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easy,nonn
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AUTHOR
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Alexandre Wajnberg & Eric Angelini (alexandre.wajnberg(AT)ulb.ac.be), Sep 04 2005
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EXTENSIONS
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Extended by Ray Chandler (rayjchandler(AT)sbcglobal.net), Sep 06 2005
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