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Search: id:A104362
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| 1, 6, 12, 60, 180, 1260, 2760, 7560, 37800, 415800, 1265040, 16287864, 113538360, 567638664, 1135134000, 19298936664, 58868650320, 1113894381120, 5499724230000, 39112247205360, 423754918508832, 10054207233388032
(list; graph; listen)
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OFFSET
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2,2
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COMMENT
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a(n) = A000203(A104357(n));
a(p) = A104350(p) for primes p.
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LINKS
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R. Zumkeller, Products of largest prime factors of numbers <= n
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MAPLE
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A000142 := proc(n) RETURN(n!) ; end: A006530 := proc(n) local i, t1, t2, t3, t4; if n = 1 then RETURN(1) ; else t1 := numtheory[divisors](n); t2 := convert(t1, list); t3 := sort(t2); t4 := nops(t3); for i from 1 to t4 do if isprime(t3[t4+1-i]) then RETURN(t3[t4+1-i]); fi; od; RETURN(1); fi ; end: A104350 := proc(n) local k, resul ; resul := 1 ; for k from 1 to n do resul := resul*A006530(k) ; od ; RETURN(resul) ; end: A104357 := proc(n) A104350(n)-1 ; end: A104362 := proc(n) numtheory[sigma](A104357(n)) ; end: for n from 2 to 30 do printf("%d, ", A104362(n)) ; od ; - R. J. Mathar (mathar(AT)strw.leidenuniv.nl), Oct 30 2006
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CROSSREFS
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Cf. A104361, A104370.
Sequence in context: A033931 A093901 A117762 this_sequence A123900 A103972 A121735
Adjacent sequences: A104359 A104360 A104361 this_sequence A104363 A104364 A104365
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KEYWORD
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nonn
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AUTHOR
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Reinhard Zumkeller (reinhard.zumkeller(AT)gmail.com), Mar 06 2005
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EXTENSIONS
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Corrected and extended by R. J. Mathar (mathar(AT)strw.leidenuniv.nl), Oct 30 2006
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