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Search: id:A100546
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| A100546 |
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Difference between the smallest semiperimeter (see A063655) and its integer log (A001414) equals 1. |
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+0
1
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| 2, 3, 5, 7, 11, 13, 17, 18, 19, 23, 24, 29, 30, 31, 37, 41, 42, 43, 47, 53, 59, 61, 66, 67, 71, 73, 78, 79, 83, 89, 97, 101, 102, 103, 107, 109, 113, 114, 127, 131, 137, 138, 139, 149, 151, 157, 163, 167, 173, 174, 179, 181, 186, 191, 193, 197, 199, 211, 222, 223, 227
(list; graph; listen)
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OFFSET
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0,1
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COMMENT
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Theorem: Except for 24, the sequence is the union of primes and 6*primes.
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EXAMPLE
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Any prime p, since it has semiperimeter p+1 and its integer log is p.
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MATHEMATICA
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logint = Function[n, Module[{vn}, vn = Transpose[FactorInteger[n]]; vn[[1]].vn[[2]] ]]; semiperi = Function[n, Min[Divisors[n] + Reverse[Divisors[n]]]]; sq = {}; Do[If[semiperi[k] == logint[k] + 1, AppendTo[sq, k]], {k, 2, 500}]; sq
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CROSSREFS
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Cf. A001414 and A063655.
Sequence in context: A020625 A033633 A117285 this_sequence A117094 A074721 A152073
Adjacent sequences: A100543 A100544 A100545 this_sequence A100547 A100548 A100549
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KEYWORD
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nonn
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AUTHOR
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Carlos Alves (cjsalves(AT)gmail.com), Dec 31 2004
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