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Search: id:A105997
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| A105997 |
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Semiprime function n -> A0013458(n) applied three times to n. |
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+0
6
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| 26, 39, 74, 77, 118, 119, 178, 194, 219, 235, 299, 301, 329, 377, 381, 454, 471, 502, 535, 565, 566, 634, 679, 703, 721, 779, 842, 886, 893, 914, 973, 995, 998, 1006, 1126, 1174, 1227, 1282, 1294, 1317, 1337, 1343, 1389, 1418, 1457, 1563, 1577, 1623, 1642
(list; graph; listen)
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OFFSET
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1,1
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FORMULA
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a(n) = A001358(A001358(A001358(n))).
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EXAMPLE
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a(1) = semiprime(semiprime(semiprime(1))) = semiprime(semiprime(4)) = semiprime(10) = 26.
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MATHEMATICA
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f[n_] := Plus @@ Flatten[ Table[ # [[2]], {1}] & /@ FactorInteger[ n]]; t = Select[ Range[ 1700], f[ # ] == 2 &]; Table[ Nest[ t[[ # ]] &, n, 3], {n, 50}] (from Robert G. Wilson v (rgwv(AT)rgwv.com), Apr 30 2005)
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CROSSREFS
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Cf. A001358, A007097, A091022, A105998, A105999.
Adjacent sequences: A105994 A105995 A105996 this_sequence A105998 A105999 A106000
Sequence in context: A043147 A043927 A050702 this_sequence A075288 A125218 A138727
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KEYWORD
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easy,nonn
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AUTHOR
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Jonathan Vos Post (jvospost2(AT)yahoo.com), Apr 29 2005
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EXTENSIONS
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Corrected and extended by Robert G. Wilson v (rgwv(AT)rgwv.com), Apr 30 2005
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