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Search: id:A100759
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| A100759 |
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Beginning with 2, least prime not occurring earlier such that the concatenation of first n terms has the least prime factor prime(n). |
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+0
2
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| 2, 7, 5, 17, 127, 3, 347, 37, 71, 829, 89, 79, 311, 271, 1103, 823, 827, 7219, 149, 499, 3947, 6367, 2861, 3673, 13781, 2281, 281, 229, 353, 1597, 191, 1879, 2609, 10993, 19961, 4789, 383, 1093, 521, 13681, 9227, 12619, 8219, 12037, 8573, 7621, 6029
(list; graph; listen)
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OFFSET
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1,1
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COMMENT
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Conjecture: Every prime is a member.
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EXAMPLE
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a(1) = 2, a(2) = 7 and the least prime divisor of 27 is 3.
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MATHEMATICA
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a = {2}; b = 2; Do[i = 1; While[Length[Intersection[a, {Prime[i]}]] == 1, i++ ]; While[ !FactorInteger[FromDigits[Join[IntegerDigits[b], IntegerDigits[Prime[i]]]]][[1, 1]] == Prime[n], i++ ]; AppendTo[a, Prime[i]]; b = FromDigits[Join[IntegerDigits[b], IntegerDigits[Prime[i]]]], {n, 2, 30}]; a - Stefan Steinerberger (stefan.steinerberger(AT)gmail.com), Dec 21 2007
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CROSSREFS
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Cf. A114025.
Adjacent sequences: A100756 A100757 A100758 this_sequence A100760 A100761 A100762
Sequence in context: A096037 A114025 A135566 this_sequence A094360 A051757 A070524
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KEYWORD
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base,less,nonn
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AUTHOR
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Amarnath Murthy (amarnath_murthy(AT)yahoo.com), Nov 23 2004
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EXTENSIONS
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More terms from Stefan Steinerberger (stefan.steinerberger(AT)gmail.com), Dec 21 2007
More terms from David Wasserman (dwasserm(AT)earthlink.net), Mar 04 2008
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